EXOTIC PETS :: FISH

Control of Algae in Freshwater Aquaria

Excess algal growth is seen by green water and/or a green blanket of hairs on the gravel, glass sides or plant leaves. In new aquaria, or where the lighting is low, a brown form will grow. Rarely, a blue or red form is seen. To eliminate algae, three conditions of the aquarium must be examined and corrected if necessary.

Lighting

Excess lighting will encourage algae, especially if sunlight strikes the tank. Always shade the aquarium from natural light and use artificial lighting, which can be controlled. If real plants are used, these require a certain intensity of light per area of leaf to photosynthesise, hence the same light levels are required whether you have one plant or one hundred. If the real plants are few in number, the surplus light grows algae, therefore plant densely or not at all.

An aquarium with plastic plants can have lower levels of lighting, just for viewing, and this will help inhibit algal growth.

Balance

The ideal aquarium has a biological balance, seen by ice-like clarity to the water with lively, colourful fish. The bacteria in the tank will balance the excreta from the fish, providing the water is regularly diluted via partial water changes (25 percent every week or two). If the aquarium is neglected, the dissolved solids from excess food, feces, plant debris and bacterially produced nitrates will fertilise the algae, encouraging rapid growth.

Feeding

Surplus food will encourage algal growth, so always feed a few flakes to the waiting fish and stop as soon as a few are left over. Remove the surplus, too. Beware of frozen or fresh foods that cloud the water with dissolved or finely dispersed nutrients.

Algae Treatment

It is no use pouring Algae Cures into a tank full of algae and excess biological matter. The imbalanced tank will just absorb the active ingredients and the algae merely falter and then start regrowing. Scrape off all the algae possible and siphon it out. Ornaments, rocks and plastic plants can be bleached clean (rinse thoroughly). Do a 25 percent water change, "hovering" the gravel with the siphon tube. Then add an algae treatment to prevent regrowth.

If you prefer to have algae in the aquarium, keep the front glass clear with a cleaning magnet or (soapless) plastic scourer. Use lots of light that favor the green over the brown or blue varieties. Algal volume can be controlled with algae-eating fish such as Sucking Loach, Bristle-nosed Catfish or a Plecostomus. Snails will not helpÑin fact they will breed until their numbers become a problem.

Avoiding Pollution

The danger of pollution from uneaten food and excreta is always a risk in any aquarium, which is why proper equipment, good water preparation and maintenance are so important. A properly prepared fish food can help to minimize the risk of pollution in several ways. A highly palatable fish food will be eagerly accepted by the fish, which means less uneaten food remains to pollute the water. A highly digestible formulation, which is utilized efficiently by the fish will also convert a higher proportion into growth and energy, thus resulting in less waste from the fish to pollute the tank.

Feeding Your Fish

Unlike humans, fish have the ability to eat continuously, digest what they need, and excrete the rest. This means it is very easy to overfeedÑnot the fish, but the aquarium. It is surprising how little food fish actually need. Unlike humans, fish are not fighting gravity or maintaining a high body temperature. Hence, little sustenance is needed to grow and swim around.

Most commercial fish foods contain all the nutrients and trace elements pet fish require. It is, however, recommended to choose a good quality one, where the manufacturer has carried out research to find the ideal level of nutrients, including vitamins and minerals, which fish require for a long and healthy life. It is important to follow the instructions on the packaging, which usually recommends two small feeds per day, and to remove any leftovers from previous feeding.

Research has shown that to stay fit and healthy and enjoy maximum longevity, fish need a wide range of essential nutrients. Without the right amount of these nutritional "building blocks", fish may cease to grow, lose colour, stop breeding, become susceptible to disease and, in certain circumstances, might even die. In their natural habitats, fish feed on a variety of plants, insects or other water-borne live foods, which are generally in plentiful supply and high in nutrients. In the confines of an aquarium, live foods can introduce disease and infestation, and problems of water pollution from a high level of fish excreta can cause stress and disease in the fish.

Nutrient Requirements

The relative amount of food needed by fish differs greatly from human beings. Humans are warm-blooded, and up to 70 percent of the calories from food are used to generate heat needed for survival. Fish, on the other hand, are cold-blooded and do not have this requirement. As fish are supported in water, they do not have to use a lot of energy offsetting the effects of gravity. As a result, fish need relatively little high calorie ingredients, such as carbohydrates, in their diet.

Another difference between human and fish nutrition is the requirement in vitamins. Fish need much greater relative amounts; this is probably a reflection of the greater sophistication of the human digestive system, where vitamins can be used more efficiently.

Proteins are built from nitrogen compounds called amino acids, which are essential for growth and the rebuilding of body tissues. However, not all proteins are easily digested and utilized by fish. Some poorer quality proteins are utilized primarily as a source of calories, resulting in the release of ammonia, which is toxic to fish. The quality and digestibility of the protein present in fish food is therefore critically important. Essential amino acids cannot be synthesised by the fish and therefore must be present in food. Two such essential amino acids are lysine and methionine.

The best and easiest way of feeding fish is to provide a complete and balanced diet free from infestation. A key factor for this is the percentage of water in the food. Micro-organisms cannot develop at a moisture levels of 4 percent or less, and flaked fish foods should therefore have a moisture level below 4 percent. Studies have shown that once prepared food is put into the aquarium, the nutrients very quickly leach out and are therefore no longer available to the fish. The longer the food is in the water, the greater the nutrient loss. This means that fish that feed in the middle and bottom of the tank may be getting their food after many of the water-soluble nutrients have been leached out.

Other foods

It's good for most fish to eat some frozen or live brine shrimp and a few live black worms. Try to alternate feeding live or frozen brine shrimp with live black worms. One day most fish get brine shrimp, and the next day they get live black worms.

Feeding Schedule

The frequency of feeding depends on the type of fish you have. Carnivores, for example, like to eat one big meal a day and then lie around digesting it, whereas herbivores tend to nibble all day. If your tank contains a mixture of fish (community tank), then a compromise is to feed two or three times a day. If you breed fish, you need to give several small meals a day, as fry have big appetites but small stomachs.

If you miss a feed, or even several days feeding, don't worry. In nature, fish often experience erratic food availability. You would, however, need to make arrangements if you go away from home for more than a few days.

How Much to Feed?

The best and easiest way of deciding how much to feed is to observe your fish during and just after feeding. If there is no food left on the surface of the water after a few minutes, give a little more until the fish stop eating, then remove the excess food. Soon you will be able to judge quite accurately how much your fish need. Food that sinks to the bottom and is not eaten will cause water pollution, so be sure all the food is eaten. Use your net to remove the food that is not eaten after ten minutes. It's fun to feed smaller fish a few of Tetra's Delecta Freeze Dried Blood Worms for desert.

Fish Health and Disease

Healthy Fish

The secret to success in keeping ornamental fish is water quality. Fish live in permanent contact with their aqueous environment and are totally dependent upon it.

Always remember that fish live in their own toilet! They excrete into the water, copiously and continuously. It is not the solids (feces) that present the major problem, but the fish's equivalent of our urine. They excrete ammonia, which is soluble and invisible, but deadly poisonous. If the aquarium (or pond) is too crowded or neglected, the ammonia builds up and poisons the fish. It irritates the gills and extra mucus forms, which reduces the oxygen uptake. The fish then gasp at the surface for air. Next, the ammonia will burn the skin and the fish start to scratch (called flashing). The fins are attacked next, leading to fin rot. At only a few parts per million, ammonia will actually kill the fish.

Owners see these symptoms and may buy an air pump, thinking that the oxygen level is low even though it isn't, and then add anti-parasite chemicals which add to the fish's irritation. Finally owners may use antibiotics, which destroy valuable nitrifying bacteria, making the situation worse. All this is unnecessaryÑall that is needed is to flush that toilet! Regular partial water changes are essential. If you use tap water, add a little dechlorinator, or at least let the water stand for a few hours to let the chlorine evaporate away.

Fish Diseases

Virtually every fish keeper experiences an outbreak of disease in his fish at some point. Many fish disease problems are actually caused by poor water conditions and not by parasites or bacteria. Hence, if a disease outbreak occurs, always first check the nitrite, pH and temperature of the water just in case one or more of these conditions is the cause. Always check the filter. A clogged or poorly working filter can give rise to water pollution, which itself can predispose fish to diseases.

Sometimes, however, the disease is caused by parasites or other disease causing organisms. Such diseases are know as infectious diseases because they potentially are able to spread from one fish to another.

Infectious diseases can be categorised as follows

Parasitic Diseases

Many of the more common parasitic diseases occur on, or just beneath, the body surface of the fish, such as velvet, white spot and flukes. Affected fish are often irritated by these skin parasites and respond by repeatedly flicking their fins or scratching their bodies in the rocks. Sometimes the gills are also affected, such that the fish may breathe heavily (fast gill beats) and it may remain near the water surface, enabling its damaged gills to take in more oxygen. Various anti-parasite cures are available from your veterinarian or your aquatic retailer.

Fungal Diseases

These generally affect fish, which are already weakened or stressed, so, always check the water conditions if a fungus outbreak occurs. Also, skin injuries caused by fighting or from rough handling in the net are prone to fungus attack. Fungus manifests as white to grey "cotton wool," like growths on the fish's body or fins. Anti-fungal cures are available from your veterinarian or your aquatic retailer.

Bacterial Diseases

These can manifest as ulcers, reddened lumps, or rotting of the skin or fins. Anti-bacterial remedies are available from the aquarium stores; however, in severe infections, antibiotics may be required, which in many countries are prescribed by your veterinarian.

Viral Diseases

These are probably more common than generally believed. One well-known virus disease is lymphocytis, which appears as small white, grape-like clusters on the fish's body or fins. Fortunately, this infection is rarely fatal. At present, there are no chemical cures for viral infections of fish. The best advice is to keep the affected fish under optimum, stress-free conditions in the hope that its immune system will overcome the virus.

Prevention is Better than Cure!

The seven golden rules for preventing diseases in fish are:

• Buy your fish from a reputable retailer or breeder and never purchase specimens which appear unwell.
• Quarantine new fish for two to four weeks, wherever possibleÑa small extra aquarium is ideal for this purpose.
• Always pay attention to the water quality in your aquarium and ensure that the water conditions (temperature, pH, etc.) are suitable for the species you keep.
• Never overstock the aquarium.
• Do not purchase fish which are known to fight or bully their tankmates.
• Remove dead or dying fish; otherwise, they may pollute the aquarium, and in some cases, can transmit diseases to other fish which happen to forage over the carcass.
• Always feed a balanced diet of high quality.

Transporting Fish

There are a few measures that can be taken to minimise risks when transporting fish. None are foolproof, since the mere act of transportation creates stressful conditions that many species of fish react adversely to. Therefore, even if the following guidelines are adhered to, stress may still occur.

Temperature

This is best controlled by wrapping the polythene bags or containers in newspapers and placing them in a polystyrene box, such as those which pet shops use for transporting their own stocks in. If this is not available, then a normal cardboard box may be lined with polystyrene tiles. If even this is unavailable, then the wrapped bags and/or containers may be packed in a box containing polystyrene chips, shredded newspaper, small pieces of foam such as those used in pillows, or even a blanket.

Oxygen

Oxygenating tablets may be used, but in the majority of cases they are unnecessary. Instead, the number of specimens in each bag needs to be kept to a minimum, and a volume of air at least four or five times as large as the volume of water needs to be allowed. The oxygenation of the water that will take place efficiently enough for most fishes' needs.

Feeding

No feeding should take place for at least a few hoursÑpreferably one dayÑprior to transportation. If food is offered too close to the time of transportation, then the feces and other excreta that the fish will inevitably produce will foul the water and may lead to losses.

Water

As far as possible, water from the tank in which the fish have been kept should be used. Raw water should be avoided except in emergencies. In such cases, it should be treated with a dechlorinator and aquarium conditioner. This will help keep bacteria and other micro-organisms in check.

Re-introduction

If some of the "old" water can be transported, then this should be used, in conjunction with conditioned "new" water (see above), to refill or re-establish the tank. "Old" gravel and plants similarly help to speed up the maturing process. Wherever possible, the fish should be re-introduced in the evening, after equilibrating the temperatures. Tank lights should be left off for the first evening and the fish should be left unfed for a day. A close watch needs to be kept for signs of trouble during the first few days, and affected should be fish treated in a separate tank. Some fish need a little longer than others to settle down after their ordeal.