Fish Problems
Holidays
What happens when I go on holiday? In most cases, the short answers, provided that your fish are generally well cared-for, nothing! Fish do not suffer from starvation in the short term, especially in a well planted freshwater aquarium. In a long-established marine aquarium, which has a good growth of algae and other organisms on the rocks or coral, fish will be able to find enough food to keep them going for a few days. The lights can simply be left on for a week’s holiday, and this minor disturbance should not upset the fish or plants too much.
If your fish are especially valuable or delicate, or if you will be away for an extended period, you can plan accordingly. Fit a time switch to the lights on the tank. Time switches can be purr-chased from any electrical shop, and are easily programmed to switch lights on and off at predetermined times.
Do not give a massive feed before you leave. Make up individual packages of food and label them ‘Monday’, ‘Tuesday’, etc, so theta friendly neighbor can drop them into the tank regularly. Cut down on the normal quantities of food just in case something begins to go wrong while you are not around to spot the first signs of trouble or to siphon out uneaten food.
Power Cuts
What about power cuts? If you think of how long it took your tank to heat up to the proper temperature after it was first switched on, you will realize that it will also take a long while for it to cool down. Most power cuts last only an hour or so, and the tempera-true in a large tank will not drop much in this time. Small tanks cool off more quickly, and can be insulated by covering them with blankets. If the temperature drops more than 4°C (7°F) you will need to take measures to warm things up. For a freshwater tank, small amounts of hot water can be added, very gradually, stirring the water well to avoid ‘hot spots’. Reheating a marine tank isomer difficult, as seawater cannot be heated as it reacts with cook in utensils. The only course is to fill a plastic container with hot fresh water and to float it in the tank, refilling it with more hot water as it cools off. In marine tanks more damage will be caused during a prolonged power cut by lack of aeration and filtration than by chilling.
Fumes and Smoke
An air pump draws any fumes in the room into the aquarium water. It’s best, therefore, to keep the pump where there will not be too many fumes. If you are painting the room, extend the tubes on the pump so that it can be moved elsewhere, or switch off aeration until the worst smells have faded. Encourage room ventilation by opening the windows, and keep the tank well covered. Fish show distress at dissolved smoke or fumes by ‘gasp-in’ at the surface, and this should be a signal to change the water or, at least, part of it.
An oily film may develop on the surface, and this can reduce the amount of oxygen dissolving in the water. It is simply removed by floating a sheet of newspaper or other absorbent paper on the surface and quickly removing it. The oil film will come away too.
Moving Tanks
If at all possible, don’t. The older types of tank with metal frames, especially the larger ones, will leak if moved, however carefully. Never attempt to move any tank until it has been emptied com-politely. All-glass tanks with bonded seams have a slight flexibility, and can usually be moved, while empty, without causing leaks.
Catching and Handling Fish
At some time, it will be necessary to catch a fish for treatment or for transfer to another tank. Your fish will have got to know their tank intimately, and will be skilful in avoiding your attempts to catch them. Chasing them around the tank is often disastrous: not only does it upset the other fish, but plants and other tank arrangements can be dislodged. It is best to stand a long-handled net in the tank for a few hours until the fish are accustomed to it, then to move it slowly so as to catch the fish against the front glass. Always transfer the fish to a bag containing water from the original tank, and be sure to equalize the temperatures before releasing it into the new tank.
A metal-framed nylon net is acceptable for freshwater fish; brutal-plastic nets must be used for marine fish. For long-spied fish, and for some very spiky Catfish, it is best to fix a polythene bag over the net frame, so that fins are not caught in the mesh and damaged.
Handle fish as infrequently as possible. If the slimy mucous coat-in over their scales is damaged, micro-organisms can enter and cause disease. Fish should be handled only when it is necessary to treat them by swabbing their skin surface, and then only with wetlands, which are less likely to damage the mucous coating.
When Thing Go Wrong
If the proper balance in the aquarium is disturbed it soon becomes obvious. Fish gasp at the surface or lie on the bottom. Discolored cloudy water means that all is definitely not well.
Get into the habit of checking regularly that you can see all the fish. A sick fish may hide away and die, quickly fouling the water. Sudden blackening of the gravel is a sure sign that things are going wrong, and you must investigate swiftly. Usually this effect is result of prolonged overfeeding, or it may be that gravel over biological filter has become too tightly packed to allow water to flow through it. Stirring the gravel gently, together with vigorous aeration and siphoning-out of the sediment you dislodge, may improve matters.
If the plants begin to die off, check that they have enough light. It is quite normal for certain types of freshwater plant to shed their leaves when transplanted to a new tank, and they will usually recover quite rapidly.
Check the tank temperature daily, especially if your fish seem tube sluggish and go off their food.
Foreign Bodies
Quite often, you will find unexpected organisms in your aquarium. Eggs and spores get carried in with plants and live food, and you may get Snails, Leeches, Worms and various other small creatures introduced in this way. Most are harmless, and their presence indicates that tank conditions are healthy; many will simply beaten by the fish.
Snails are unsightly and, contrary to traditional advice, is an unnecessary nuisance in the tank: they eat plants and foul the tank with their droppings. They can be removed or crushed against the glass and left for the fish to eat. You can collect snails for disposal by floating a lettuce leaf in the tank overnight: by morning, the snails will have congregated on it, and the whole can be removed.
Malayan sand snails are the only type which might be worth introducing. They are small elongated freshwater snails which live buried in the gravel. They fulfill a useful scavenging job, and their constant burrowing prevents the gravel from becoming too tightly packed and anaerobic.
Leeches are brown or grey worm-like creatures which sometimes feed on the fish. They should be caught and killed whenever possible. Ideally, one would wish not to introduce them to the tanking the first place and you can dip any new plants, to which the Leeches might be clinging, in a dilute salt-water solution before putting them in the aquarium; unfortunately, this process often kills not only the Leeches but the plants as well. One way of dealing with the problem is to introduce to the tank a Puffer fish (Tetra Odon sop.); with luck, this will eradicate the Leeches by the simple process of eating them; it will also eat snails — shells and all.
In the marine tank, many unusual organisms may appear, especially if live Shrimps are fed to the fish or if live corals or other invertebrates are introduced. Many marine organisms grow from young who float almost invisibly as plankton, and the adult forms may develop in your aquarium. Usually, as soon as these creatures are big enough, they are eaten by the fish, which con-scantly search through the gravel and in cracks in the coral for suitable food. Only very seldom will these ‘foreign’ organisms cause problems.
Leaks
If a tank springs a leak it is usually only a gradual seep along one edge. You will need to empty the tank to affect a cure. Dry it out very thoroughly, and then run a fillet of silicone-rubber adhesive (obtainable from aquarium dealers) right down the affected edge on the inside of the tank. The fillet can be smoothed and shaped with a finger to make it unobtrusive. Do not just apply a patch over the point where the leak appears; water may be running along beneath the surface of the existing silicone or mastic and popping out somewhere else. Before refilling the tank, allow the silicone to dry or cure for at least 24 hours, as it gives off toxic fumes of acetic acid.
Equipment Failures
Because unusual problems can arise, it is wise to own a spare set of thermostat, heater and cheap plastic tank.