Welcoming and feeding your fish

Choosing compatible fish

Read up on each species before buying it: adult size, water, shoaling or solitary life, temperament. Some species must live in a group, others are territorial or aggressive and do not tolerate their neighbours. The simulator cross-checks this information for you and flags risky combinations.

For a first tropical tank, OATA lists hardy species: tetras, guppies, mollies, platies, swordtails, corydoras and gouramis. Browse them in the catalogue to compare their needs.

Transport and acclimatisation

Before buying, check that the ammonia and nitrite in your tank are at zero. Go straight home: bright light, extreme temperatures, noise and jolts stress the fish in their bag. At home, they then need to be gradually accustomed to the temperature and chemistry of your water.

For sensitive species, or if the shop’s water is very different from yours, the drip method is gentler: the fish and their water are placed in a container into which tank water drips slowly, until the two waters are identical. It takes from one to several hours, for example for discus.

Leave the light off for the rest of the day and keep an eye on the newcomers and the water quality during the first week.

Quarantine

A fish can carry a disease without showing any signs. Quarantine means keeping newcomers in a separate tank for two to four weeks before introducing them into the main tank. It is especially useful if your tank has not received new fish for a long time.

• A small tank equipped with a heater, an already mature filter (or filter media taken from the main tank) and a few hiding places.
• The same water as the main tank: fill it with water from it as much as possible.
• Feed normally and change the water every week.
• Use a net and siphon kept only for this tank.
• If there are no signs of disease at the end of the period, the fish can join the main tank.

Feeding without excess

The RSPCA advises giving what the fish eat in two to five minutes, in two or three small meals a day rather than one large one. Any uneaten food breaks down into ammonia: overfeeding is one of the main causes of polluted water.

• Vary the diet: basic flakes or granules, supplemented with frozen prey (daphnia, brine shrimp) that has been fully thawed.
• Think of the bottom: bottom and midwater fish need food that sinks, as tablets or granules.
• Respect feeding times: nocturnal species, such as some catfish, feed in the evening, with the lights off.
• Match the diet: plecos and other grazers need vegetables (courgette, spinach) and sometimes wood to rasp. Each species’ diet is given on its profile.

Never release a fish

An aquarium fish released into the wild usually dies; if it survives, it can seriously harm the local wildlife. The mosquitofish, introduced worldwide to fight mosquitoes, now threatens small local species as far as southern Europe. Never empty a tank’s water, substrate or plants into a river or stream either. If you can no longer keep a fish, offer it to a fish shop, a club or another hobbyist.