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Aquarium Fish Keeping
Fishes are cold-blooded vertebrates meaning that they maintain the same temperature as that of water. They breath oxygen dissolved in the ambient water through gills, which are leaf-like organs generally four on each side of the neck in a pouch covered by operculum. The gills are richly supplied with blood vessels & water is swallowed from the mouth and forced over the gills. There are two paired viz. pectoral & pelvic fins, three unpaired viz. dorsal, anal & caudal fins. The fish body is composed mainly of a large lateral muscle on each side of backbone, divided by sheets of connective tissues into segments corresponding to vertebrae, which give rise to typical flaking of the cooked fish. This is the main organ for swimming. Fishes also possess a characteristic organ, the air-bladder lying in the body cavity & filled with gas. Its main function is to control the specific gravity of the fish. Careful examination of the majority of the fishes would reveal a line running from the heads along the side of the body. Its function is to detect vibrations of low frequency. Most fish move by body movement and not by fin movement. The fins are mainly balancers with the exception of tail fin which often acts as rudder, propelling the fish. In fast swimming, the action is initiated at the head end of the fish and waves passes down the body, culminating in a flick of the tail. The dorsal and anal fish prevent the fish from turning over in the water, the paired fins also braking and turning functions. Compared to this in slow swimming, the pectoral fins are used. The balance of fish is also controlled by inner ears, muscles and even the eyes. The rate at which fishes consume energy, produce heat and waste products and consumes oxygen is called its metabolic rate. An understanding of the factor, which modify it is a primary importance to the aquarist.
Since fishes are poikilothermal animals, they differ fundamentally from ourselves in that they have increased metabolic rate as the temperature rises and are hungriest when warm. Another factor influencing the metabolic rate is activity. A resting fish consumes less energy than an active fish. The higher the temperature, the more energetic a fish tend to be so that an elevated temperature acts doubly in causing greater energy consumption.
In general, fishes are adopted to the temperature variation of their natural surroundings. However, the sudden exposure to a change in temperature is likely to cause a shock followed by disease. For safety, it is always better to avoid rapid change of more than 20 C in either directions. The usual symptom of chill is very characteristic slow motion, swimming without getting anywhere called shimmies & development of disease called ‘white spot’.
Aquarium keeping is a fairly common hobby in Western World. The keeping of brightly coloured small-sized fishes in small indoor tanks was seriously undertaken only in the middle of last century when in Britain and other Eupropean countries a considerable interest in the subject developed . At the beginning of present century aquarists began to keep tropical fishes, and it was perhaps the essential artificially of so doing that started a new wave of successful fish culture. The aquarists were obsessed with copying nature in the tanks. Thus, aquarium gradually came to be regarded as most of us see today, as an artifact, of a mirror held up in nature.
Aquarium Keeping Tips
A good aquarium is a planned fish community where the shape, size and layout are all important. The glass bowl of earlier years was soon replaced by a rectengular glass tank, either made wholly of glass or with a metal frame and glass sides and a bottom of glass, slate or other rigid material. An ideal size of the aquarium is 50X30X30 cm and it is a favourite size. Smaller size aquaria do not accommodate adequate fishes or allow proper movement of fishes. Larger aquaria are very attractive & give scope for beautiful planting arrangement, but they are expensive and difficult to manage. In general, tropical fishes can be housed in smaller tanks, this is because they are usually smaller and are also able to withstand a relative deficiency of oxygen in the water. An aquaria of the above stated size can comfortably house six to eight 25-30 mm gold fishes or guppies. This would hold 1 cu.ft. of water with a surface area of one square foot. To find out how much water an aquarium would hold, following formula is used:-
(Length in inches x Width in inches)/1728 =capacity in cubic foot
while the largest possible surface area is highly desirable, it does not make an attractive tank if the depth is too shallow, so it is best to strike an average taking both biological & artistic consideration into account. We compute aquarium’s carrying capacity from surface area taking several other related factors such as waters temperature, movement, dissolved oxygen content etc. in consideration. However, the warmer the water the lower the solubility of oxygen and thus, reduced carrying capacity of aquarium.
WATER QUALITY
Tap water is generally chlorinated and as such it is essential to keep it stagnant for a day or two. The process is called conditioning and it helps to get rid of chlorine. Chlorinated water can also be rendered safe by addition of 0.5gm of sodium thiosulphate per gallon of water. Rain water, melted snow or distilled water are quite safe in aquariums. While keeping aquarium, the temperature of the water should always be kept in sonsideration and the ideal temperature for tropical fishes is 20-30°C.
In aquaria, thewater may become cloudy for number of reasons, greenishness is caused by crowding of unicellular algae. It is a fundamentally healthy water, but spoils the appearance of the aquarium. If not changed, the further assemblage of various segments & decay of algae in the aquarium affect the water chemistry. As such, the water must be changed at this stage. Clarity, moderate light, optimal number of fishes, underwater plants help to prevent green cloudiness of the aquarium. Aquaria with electric illumination never develop green water mainly because they do not receive excessive light. Acidity of the water make for cleanliness but not good for plant growth. It is often said that a partial or nearly complete change of water only serve to stimulate further alga growth, however this doesn’t always occur and green water may be cured immediately by siphoning it off alongwith faecal matter or detritus, and replacing it with fresh ‘conditioned’ water.
Grey cloudiness is another problem reported by many aquarium keeper. It often follows with the setting up of tank, sometimes because the sand was not washed thoroughly, but often due to burst of animal life which starts ahead of algae. This is attributed to infusoria, bacteria, fungi or just dirt. The cloudiness caused by dirt or infusoria usually disappear in a few days and is not dangerous. Bacterial or fungal cloudiness is a bad sign and usually caused by excessive organic loading. Although attention must be paid to the basic causes, such as over crowding, grey cloudiness may often be temporarily corrected by brisk aeration or by use of antibiotics. Another effective method for correcting grey or green cloudiness is to place one or two large fresh water mussel in the aquarium.
SETTING UP A TANK
The first important consideration in setting up an aquarium is its location. It should preferably receive some daylight & perfect illumination. It is suggested that an aquarium should receive 8-10 hours of illumination and should not receive more than two hours of direct sunlight.
SAND OF GRAVEL
The purpose of the sand is to hold down rooted plants and to provide decoration. If it is too fine it packs tightly and prevent the roots from penetrating as well as promote growth of anaerobic bacteria. And if it is too coarse, the plant get little grip & uncensored feed get down to the sand. Thus, coarse river sand, preferably with variable grain size is the best. It should be deep enough to promote adequate root space for the plants provided. The placing of deep sand at the back also look pleasant, provide site for largest plants & encourages mud to accumulate at the front of the aquarium from where it is easily removed. Before use sand must be thoroughly washed in 10-15 swirling in fresh buckets of water. Some aquarists prefer to use stones, roadwork & ornaments, but it is purely a matter of personal choice.
PLANTATION
An aquarium without plants is like a garden without flowers. Even the highly attractive exotic fish cannot be shown to advantage in an aquarium devoid of vegetation for it is the contrast of varied colours of fishes with natural background that we create the charm in fishes appearance and movement.
Plants not only provide decoration and natural setting, but also exygenate the water by photosynthesis. The fishes and plants have symbiotic relationship and contributes in the sustenance of each other. Before putting new plants in the aquarium one should ensure that they are clean & free from germs encrustation. To do this, rinse them under tap and remove yellow or decaying leaves. They can then be immersed in 2% salt or lime water. While introducing plants in the aquarium after it has been filled with water, a pair of planting sticks would be found useful. Push the plant into the sand with one of the sticks and heap sand around the roots. If plants are not firmly anchored into the sand their buoyancy causes them to rise to surface. Plants with small roots can be anchored with thin strip of lead wound around their base. Plants should never be bunched closely together. They should be planted to allow water and light to reach the stems. The commonly used plants in aquarium are :-
- Eel grass (Valliseneria spirals): is a tall plant with grass like leaves, light green in colour & rise vertically from the crown to the top of the water where they float along the surface.
- Sagitaria sp : Similar to eel grass, it is a moderate sized plant & well suited to aquarium of 30 cm depth. The leaves of this plant have characteristic arrow-like shape.
- Hornworth (Ceratophyllum sp.): The plant gives a real beauty to the aquaria, but for two draw-backs. The leaves are highly brittle & the plant has no real roots.
- Hydrilla verticillata: It is a most common hydrophyte, easily available and as such, used by majority of aquarium keepers. The green whorlly leaves not only give beautiful appearances but also substratum to sticky eggs.
- Indian fern (Ceratopteris thalictroides): Though not a true fern, the leaf formation is similar to ferns, the submerged fronds being attached to stems that are ratherbrittle & rise from a crown. If planted in deep waters the stems may reach a length few feet.
- A number of other rooted or floating plants are also used by aquarist viz. Cabomba, Myriophylum, Cryptocoryne, Amazon etc. depending upon choice of aquarium keeper or their availability in the area.
AERATION
There are lot of misconceptions among the aquarists about the aeration & aerators. It is generally understood that aerators force air or oxygen into the water which, in fact, is not the reality. Under usual conditions, the bubble released by aerators serve to stir the water. The usual method of aeration is to release bubbles through porous stones, kept at the bottom of the tank. Corborundum stones give the finest bubbles, but also need the most powerful air-pressure. All stones tend to clog, especially when not used with pressure and should be removed dried and reset. Fine rubber or plastic tubing should be used to lead air from pump to the stones. It is suggested that small bubbles of an average diameter of about 1/12 cm, an aerating stone delivering 32 cm³ of air/mt is adequate in 70 lit. tank. Air pumps, spray & drips are also used as effective methods of aeration.
HEATING
In colder places, the aquariums are heated electrically with a control known as thermostat, which is set to keep the tank at uniform temperature all the time. Of course, the thermostat works only downward and if the outside temperature rises above that set by the thermostat it cannot prevent the aquarium from getting the warmer too. The thermostats are non-submersible and clipped on to the sides of the aquarium. It has a glass body with the condenser inside it and control which consist of a small adjustable screw with a non-conducting portion so that the operator can alter the setting of the bimetallic strip and hence, the temperature. Some combination models of thermostat and heaters are also available in the market. A good thermostat has a small differential, which means that it does not allow the water to vary by more than a degree or two temperature.
Electric heaters may be of glass or metal exterior and they may be totally submersible or so constructed that their tops must not be placed under water. Essentially, a heater consist of a heating coil, wound on a ceramic or glass. This may be surrounded by a layer of fine sand or left bare inside the tube, which is sealed with a rubber cap. Submersible heaters are water tight. The resistance wire usually of thin microbe or similar alloy, heats up as does an electric radiator element and it is, therefore, necessary to make sure that business part of the heater is covered by water otherwise it will fuse. Total submersible heaters are quite popular as they heat more efficiently. The heater should never be buried in the sand.
FEEDING
The most important thing to remember about feeding is that over feeding is single major cause of fish mortality and pollution in aquariums. The fishes are cold-blooded animals as such, one should never draw parallel of feed requirement of fish with human beings. The wisest motto in feeding is that hungry fish are healthy fish. Not too much and not too little are ideal. The appetite of fish is linked with environment, the warmer the ambient water the faster they breathe, metabolise and hence need more food. The gold fish need almost no feeding in peak winter & during normal cold weather should be fed only 2-3 times a week. The quantity of feed should be such that it is consumed within five minutes and one should siphon off left-over particles. Aquarists are well supplied now-a-days with variety of dry feed and these can be used with confidence. A good all purpose dried feed should be well granulated, have uniform particles. It should also have high sinking ratio. It should afloat for a longer period and compounded with 20-30 of animal material. The ingredients commonly used in the formulation of fish feed are cereals, dried shrimp, egg etc. it is quite common to make a stiff paste of egg and water of floor and water, drying it and then grounding to convenient sizes.
Live feeds are extremely valuable addition to diet and these are used by many aquarists. The common one’s are Daphnia, Cyclops, Tubifex, Infusoria and Rotifers. It must be remembered that while feeding fine meshed dry feeds, they should never be sprinkled on water surface as much of it will remain uneaten & decay. The best method is to make a stiff paste by the addition of little water, then put the paste with a small muslin bag. To feed screw the bag so that it squeezes the paste into a ball & then dip it into aquaria.
BREEDING
Breeding of aquarium fishes fall under two categories i.e. those who lay the young ones (live-bearer) and
those who lay eggs. The live-bearing fishes are easiest to breed, but the only problem encountered with them is that of saving the young from the cannibalism of their parents. They breed all the year round under congenial conditions. In natural conditions, however, reproduction is seasonal. There are often a lafge difference in the size of sexed – males being smaller. This is particularly obvious in guppies in which male is also coloured and may have long decorative fins. Markedly smaller males also occur in Poecilia sp. Quintana sp. Psedoxyphorus spa. Cambusia sp. Most liverbearers produce young at about 22 day interval.
The egg laying fishes are quite different from the live-bearer and include most common fishes viz. gold-fish & zebra fish. The gold-fish lay adhesive eggs which stick to water plants while zebra fish lay non-adhesive eggs which falls to the bottom. The hatching rate of these eggs depend on number of factors viz. water temperature, hygienic condition and extent of predation. The majority of fish eggs hatch in one day or within few hours in temperature ranging from 25-30°C. In lower temperature the hatching period is increased. When the eggs hatch, the young fry still have a yolk sac. The colouration of hatchings usually take few days to a month or so.
Common Aquarium Fish
i. Black molly (Molliensia sp.) :- Recognised in view of its colour which is highly black. It is a live-bearer fish normally found in rivers.
ii. Golden gourami (Trichogaster) :- It has long thin whiskers in place of breast fins. They use the whisker for locating the feed, and putting and greeting the colleagues.
iii. Black tetra (Hyphessobrycon sp.) :- It is a beautifully marked little fish which rarely grows more than 50 mm in tanks. Being of peaceful disposition is an excellent fish for aquariums and its habit of schooling make it distinctive when there are two or more fishes in the aquarium.
iv. Zebra fish (Brachydanio rerio) :- It is probably the most popular of all small egg laying fishes. They can withstand a greater range of water temperature. They normally move in shoal. They can be easily bred in aquariums.
v. Guppy (Lebistes reticulates) :- it can withstand a wide range of temperature ranging from 15-35°C. Guppy eat plenty of food and can be fed more often then most fishes in the aquarium. Dry feed, Tubifex, boiled spinach are all acceptable to these fishes.
vi. Fighting fish (Betta splendeus) :- The fish reaches a length of about 50-60 mm. The fish is so pugnacious that no males can be kept together, although one is perfectly peaceful in an aquarium. The fish is a bubble nest builder and show sexual dimorphism only at the time of breeding.
vii. Kissing gourami (Helostoma temmincki) :- It takes its name from curious kissing action. In wild the fish reach quite a good size, but in aquaria they rarely grow more than 100 mm. The temperature range of gourami varies from 20-30°C.
viii. Angle fish (Petrophyllum sp.) :- It is one of the most popular ornamental fish throughout the World. The specimen acquire size range of 50-80 mm. It is a timid fish and as other fishes often bully it. The temperature tolerance range from 20-30°C. Like all other Cichilds, its breeding is quite difficult. Sexes are difficult to distinguish.
ix. Gambusia sp :- It is the first live-bearer which became popular. The male attain a size of 20-25 mm while female 40-50 mm in length. It is one of the easiest fish to breed, but being carnibalistic, the young need plenty of cover to hide from parents. The fish likes temperature of about 30-35°C. It is not a true aquarium fish, but some people have fancy for this fish in view of easy breeding and availability.
Goldfish (Carassius carassius) :- The most common ornamental fish in Indian aquarium. The fish is highly attractive, easy to breed. The temperature tolerance range from 18-35°C. it grows upto 60 mm in the aquarium.
Aquarium Safety Hazards
Keep your finned friends safe and sound by following a few basic steps.
Aquariums may seem secure, but within those glass walls lie several safety hazards that can injure or even kill your cherished pets. Watch for these dangers.
Electrical Shock
Most aquarium equipment and accessories use electricity making electrocution a potential danger for both you and your fish. Broken light bulbs or frayed wires in aquarium covers can slip into tanks. Cracked glass and exposed filaments on heating units can also spell trouble.
Ground all electrical cords and make sure outlets include built-in circuit breakers. If possible, let cords hang loose so they drop below the outlets. This keeps water droplets from running directly into the wall socket.
Power Outages
Since aquariums depend on electrically driven pumps, filters and heaters for water-quality maintenance, these self-contained ecosystems can suffer during power outages. For such emergencies, keep a spare battery-operated oxygen pump on hand. And, if you own an expensive marine collection, consider buying a generator to make sure your exotic beauties survive the storm.
If the room temperature gets too high during summer outages, add cool water to stabilize the temperature and oxygen content, and remember to dechlorinate the water as needed. Frigid water temperatures in winter can be just as detrimental. Be sure to cover aquariums with heavy blankets to reduce heat loss and add warm dechlorinated water to stabilize the temperature.
Air Pollutants
Many airborne particles and chemicals easily dissolve in water. So avoid using household cleaners, insecticides or pesticides around your tank. Fish’s gills are sensitive to chemical damage, which can cause suffocation and death.
Cover Up
Unfortunately, certain athletic and brave fish species may attempt to fly the coop. If you discover a motionless fish on the floor and he’s not completely dried out, put him back in the tank. Many fish should survive their brief encounter with the outside world and will be just fine. You can prevent such unauthorized furloughs by keeping a tight-fitting cover on your aquarium at all times.
Always monitor survivors closely for signs of skin infections because their protective mucous layer may be damaged.
Maintaining Your Aquarium
Make time to maintain a quality ecosystem for your pet.
Once you’ve stocked your aquarium with plants and fish, a pinch of food is all it takes to keep your pets happy and healthy, right? Wrong! An aquarium requires daily maintenance to ensure your fish’s home remains inhabitable. Here’s what to do:
Keep the Water Clean
Clean water is critical to your fish’s long-term health. Remember to change 25 percent of the tank water every one to two weeks. This routine assists in maintaining proper pH levels, decreasing the number of disease-causing organisms trapped in the gravel bed, and removing waste by-products, such as ammonia, nitrites, and nitrates.
You can buy kits that test the pH levels, water hardness, and dissolved oxygen in your aquarium: These are relatively inexpensive and detect potential problems - so you can correct them before your fish suffer.
Monitor Water Temperature
Drastic water temperature changes can kill your fish or make them sick. Be sure your heater functions properly by checking the temperature daily. Toasty 75 to 80 degree temperatures suit most aquarium fish.
Don’t Forget the Food
Feed your fish a nutritionally complete diet once or twice a day, but don’t offer more than they can consume in five minutes. Excess food just adds to your filter’s workload.
Care for Your Plants
If your aquarium includes live plants, remember to use fertilizer, remove dead leaves, and change the full-spectrum lights every six to 12 months. Plants not only provide security for shy fish, they also contribute to a healthy aquatic environment - they use ammonia and nitrate waste from fish to grow and, in turn, give off dissolved oxygen fish need to breathe.
Give Your Tank a Monthly Scrub
As tanks age, algae and debris accumulate on the sides of the tank, in tubing and filters, and on accessories. Keep your pet’s home tidy with monthly cleanings. Chemical cleaners can kill fish and filter bacteria, so use lukewarm water - hot water can destroy biological activity.
Automated and manual siphoning devices clean the gravel bed and help with weekly partial water changes. Magnetic cleaning blades or scrub brushes with long handles help you stay dry while removing stubborn algae from the tank’s sides.
Occasionally dismantle filters and lift tubes to remove clogged debris. Stiff brushes come in every length and diameter and make it easy to invade every nook and cranny.
Keeping up with these simple tasks is a small price to pay for the joy and company of your little swimmers.
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Scavengers: Natural Aquarium Cleaners
You’ve been careful to keep your fish tank clean and feed your finny friends small amounts of food on a regular basis, but all of a sudden you realize there’s algae growth in your tank. Algae thrive on the food your fish inevitably miss, and because no filtration system exists that can collect all the particles of food and waste in the tank. What’s a pet owner to do?
One solution is to introduce scavengers to help clean up your tank, but introducing scavengers has to be undertaken carefully or you may end up with a solution that’s worse than the original problem.
An Algae Primer
Most people think of algae as a plant, but it actually shares characteristics with bacteria as well as plants. Like bacteria, algae reproduce by cell division or the production of spores. Algae act like plants in contributing to the nitrogen cycle through the use of photosynthesis, which changes carbon dioxide into oxygen and causes fluctuations in the organisms’ pH and oxygen levels.
There are over 25,000 known species of fresh and saltwater algae and probably a lot more waiting to be discovered. Algae can be single-celled organisms invisible to the naked eye or can form multi-celled colonies that can grow up to 164 feet long and resemble seaweed. All forms of algae are an important part of the aquatic food chain. There are five basic groups of algae, some harmless and others capable of introducing highly poisonous toxins into your aquarium:
- Green Algae inhabit marine and fresh water environments and can be single-celled or filamentous weed and seaweed. In an aquarium, algae can cause green water, which can only be countered by making a major water change.
- Yellow-Green Algae and diatoms live primarily in freshwater, but have been found in saltwater, damp water and tree trunks. This group creates fine hair growths over your rocks, decorations and plants.
- Blue-Green Algae are found almost anywhere including on land, in the water and even in the air. This group is the most primitive and dangerous type of algae because it is the most closely related to bacteria. Some species are capable of introducing highly poisonous toxins into your water. Blue-green algae aren’t always blue-green; sometimes they’re blackish, greenish, brownish or reddish.
- Red Algae are an attractive marine group that range from small single-celled organisms to large branching seaweed.
- Brown Algae are another mostly marine group that’s more common in cooler water and includes large seaweed-like kelps and wracks.
It’s important to make sure your aquarium doesn’t have too much of the wrong type of algae, but it’s also to important to maintain balance because some types of algae can add valuable micronutrients to your fish’s diet. One easy way to maintain this balance is to introduce algae feeders into your fish tank.
Scavengers
There are a wide variety of freshwater and saltwater scavengers available, including fish, snails and shrimp, to help rid your tank of excess algae. It’s important to choose carefully though because some of these scavengers are more trouble than they are worth.
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Freshwater Scavengers and Algae-Eating Fish
Chinese Algae Eaters are well adapted for scraping algae from flat surfaces because they are sucker-mouthed bottom feeders.
Flying Fox or Trunk Barb eat all kinds of plants, algae, prepared and live foods, but they shouldn’t be kept with others of the same species.
Loaches are traditionally recommended as scavengers, but not all species are suitable for this role and some have to be fed just like other fish. Effective scavengers include coolie loaches, dojo loaches, dwarf loaches and sucker loaches. One caveat about sucker loaches is that when mature they can nip other fish and may latch onto flat-bodied tank mates in the absence of algae.
Siamese Algae Eaters enjoy red algae as juveniles, but older fish prefer flaked food. This fish is commonly available in Europe and from a growing band of US outlets.
Plecostomus Catfish are more commonly known as Plecos and are included in the 70 species of sucker-mouthed catfish. Plecos are probably the most popular of the catfish species. These fish are such dedicated algae eaters that you’ll have to supplement their diet with vegetable flakes.
Freshwater Shrimp
Bumble Bee Shrimp are not very keen on algae, but will clean up food particles from the bottom of your tank, which can help control the growth of algae. These shrimp will also have to be fed.
Ghost Shrimp are algae eaters and scavengers, but they also have a reputation for eating small fish and for stealing commercial fish food from your other fish.
Mountain or Rock Shrimp are true scavengers, but they grow to almost 5 inches long and may make a meal of smaller fish.
Yamato Shrimp eat soft algae, but because they’re not capable of feeding from the side of your tank, they prefer soft-leafed plants and fish food. These shrimp are also sensitive to shipping and are currently available only in the coastal US.
Freshwater Snails
It’s not a good idea to deliberately introduce snails into your tank because they’ll make a meal of your plants before they even notice your algae. However, you’ll probably end up with them anyway because snail eggs sometimes come attached to purchased plants. If you need to get rid of small snails, clown and skunk loaches are among the more efficient snail-eating fish. Some larger snails such as the golf-ball-sized apple snail may be an attractive addition to your aquarium, but you’ll need to think of them as a two inch fish for stock calculations. Apple snails have also been known to snack on sleeping fish.
Saltwater Fish
Butterfly fish do eat algae, but they also require a mixed diet so they cannot be relied upon to clean your tank.
Surgeons and Tangs both thrive on algae colonies, but if no algae are available you’ll need to feed them blanched vegetables to supplement their diet.
Wrasse and Hogfish in their juvenile stage will act as cleaner fish by picking parasites from their neighbors’ scales.
Batfish have been known to scavenge around piers and other structures for their food, but they’re not the best choice for a home aquarium because they can grow to twenty inches in length.
Blenny of several species, particularly the bicolor blenny, browse the bottom for algae.
Goby are bottom-dwelling carnivores who often live in harmony with shrimp. Gobies cannot however compete with most fish for food and must be kept in a mature reef system.
Crabs
Hermit Crabs are confirmed algae eaters who’ll also clean up waste food. Be careful to pick a species that only grows to one inch or less, like the left-handed hermit or the blue-legged hermit, because some of the larger species will kill fish and snails. It’s also important to provide your hermits with larger shells to move into when they outgrow their original homes.
Emerald Green Crabs live among rocks and enjoy dining on algae. They’re also very small, less than one inch at maturity, and are considered safe to keep with other fish.
Sally Lightfoot Crabs eat bubble and hair algae. They’re also very shy and may hide in your tank until they get used to their new environment.
Arrow Crabs are excellent scavengers, but they’ve been known to pull feather duster worms out of their tubes with their long claws. They may also eat other invertebrates.
Saltwater Shrimp
Coral Banded or Boxer Shrimp are notorious scavengers, but they’ve also been known to eat very small fish and attack other shrimp species. It’s a good idea to keep only one unless you’re planning to breed them.
Red or Fire Shrimp are good scavengers who’ll eat almost anything that’s offered. They are also used occasionally for parasite control because they eat the protozoan that’s responsible for Ich.
Pacific Clown Shrimp live with clown fish within the tentacles of anemones and will clean up scraps of food from your tank.
Saltwater Snails
Turbo Snails grow less than one inch long, and they will browse the surface of your glass in search of algae. They work wonders cleaning your aquarium glass, but they’re not very good at cleaning rough surfaces. There are many different species of turbo from which to choose.
Pipipi Snails are smaller than turbos, usually only growing to half an inch, and they get along with hermit crabs. These pint-sized snails will reside on the glass of your tank and keep it free of algae.
Other Saltwater Scavengers
Sea Urchins live principally on algae and some species, such as the pink pincushion urchin, make much better aquarium inhabitants than others. If you’re thinking about adding a sea urchin to your aquarium, do your research carefully because some species have venomous spines and can inflict a nasty sting. Another thing to consider is that sea urchins are a favorite meal of the triggerfish.
Starfishes and Brittle Stars can be good choices for your aquarium because they’re alga eaters who also browse the bottom looking for scraps of missed food. It’s important to research your choice carefully, though, because some species have been known to eat sleeping fish or attack other invertebrates.
If your tank is looking a little dingy and you don’t want to add chemicals, you might want to consider adding some scavengers to help clean up the algae and to add a little color to your underwater world.
Sense, Intelligence And Communication
Your fish goes about his daily life with two primary concerns -- eating and avoiding being eaten. Propelled by these basic survival instincts, your fish employs all of his senses towards self-preservation and the propagation of the species.
At the same time, your fish is a living creature who can sense hunger, pain and threat, becoming aggressive when hungry and fighting for territory when challenged. Like any other pet, your fish can communicate with you if you know how to interpret his signals. To get a better grasp of the language your fish uses to communicate with you, it’s important to understand how your fish functions and how he interacts with the environment.
Eyesight And Color Vision
Optimized to see at short distances, fish eyes have evolved to adapt to the environment in which they live: nocturnal fish have large eyes; muddy river dwellers have small eyes; and some cave fish are totally blind. In a brightly-lit habitat, your aquarium fish will have average-sized eyes.
Tests using colored cards, stimulants and the fish’s heartbeat have confirmed that all fish recognize color to some extent. As well, many strikingly colored fish species use their pigmentation to either ward off predators -- Lionfish, for example -- or to attract mates. Male Guppies, for instance, are markedly more colorful than females while some Blennies and the Thicklipped Gourami change color at spawning time.
Your fish cannot adjust quickly to varying light conditions, however, with some species needing up to an hour to adapt to new light levels. If you turn your aquarium’s overhead light off or on, you should wait a few minutes until your fish have adjusted to the new lighting conditions before you feed them.
Good Vibrations
Sound travels nearly five times faster in water, and your fish is well equipped to detect it. Even without a middle and outer ear like other animals, fish can "hear" sound through the vibrations in the water. Your fish has a lateral line running along the sides of his body, porous and filled with water, that picks up disturbances in the water. For example, if there’s a feeding frenzy going on somewhere in the tank, your fish will "hear" it through the water and rush to join the action.
Aside from the lateral line, your fish has an inner ear called an otiolith which functions very much like the human ear drum. And like the human inner ear, his "ears" help him maintain orientation and balance through cilia that send messages to the brain.
Because the tank walls and the water will reflect the sound waves, normal noise from your fish aquarium’s surroundings, such as conversation in the room, is not loud enough to be picked up by your fish. However, if you tap the tank, stand or table holding the tank or if you scrape the lid against the sides, you will send very loud noises into the water, noises that could cause shock and a great deal of stress to your fish.
Sense Of Touch
Surprisingly, fish have a highly developed sense of touch. Angelfish and Gourami use their pelvic fins not only as warning devices when coming out of a hiding place but also to grope and feel for food. Some varieties, like the Blue Gourami, have long whisker-like protrusions close to their pectoral fins which they use to both assert dominance during a territorial dispute and to help feel their way around. Catfish use their barbels to feel, dig through mud and gravel and taste food.
Taste Buds?
Yes, fish do have taste buds, even if they don’t have tongues. Depending on the species of fish, these taste buds can be situated anywhere on the body. Catfish have taste buds on their barbels -- to detect the strongest taste of food. They circle until their barbels pick up the "scent" and then zero in on their prey.
Some fish have taste buds on the skin used to send the food message to the brain where it is interpreted and the fish swerves towards the food. In species such as Goldfish where the taste buds are in the mouth, sensing is via the vagal lobe, the most highly developed part of the brain in fish. When your fish "tastes" something that is inedible, he’ll immediately expel it.
Fish Can Smell, Too?
In fish, "smelling" is linked to tasting, and it is often difficult to distinguish between the two. A fish’s scent and sense of smell, in effect, serve as a means of communication within groups of fishes. Certain "odors" are emitted by fish into the water to denote their rank and position within the group, and males are aroused by the scent that a female fish will give off to indicate that she is ready to mate.
Communicating With You
Most of the time, your fish’s behavior can alert you to a problem in your aquarium. For example, aggressive behavior or attacking plants by a normally peaceful fish may be a sign of hunger or of stress. Some fish become territorial as they reach adulthood, requiring you to make the appropriate changes in your aquarium.
Some of the larger aquarium species like Oscars, Pacus, Triggerfish and Groupers can be hand tamed, and may even recognize you when you enter the room. And the most evident manner by which fish communicate is when the hungry ones learn to follow you, or your hand, as you approach the tank to feed them.
Intelligence in your fish and the extent of his ability to communicate with you is a reaction to the stimulants within his limited environment. Therefore, if you wish to maintain a healthy and happy aquarium, watch your fish’s natural behavior and interpret it on his level. It’s as simple as that.
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