FAQ: Supplies for fish

Usually the filter creates enough flow. Extra flow pumps are used in large, marine or river-biotope tanks where stronger water movement is needed.

No fish will clean the tank for you. Corydoras pick up fallen food, and some catfish, shrimp and snails eat algae, but they also need feeding and produce waste themselves.

Use two nets: gently guide the fish towards one with the other. It is easiest before feeding or with the light off, and some fish can be lured into a clear container with food.

The net should be big enough for the fish to fit without bending, yet small enough to move between the decor. For small fish and shrimp, choose a fine, soft net that does not damage fins.

Yes, if someone looks after it at weekends and during holidays too. The heating or air conditioning should not cause big temperature swings, and the tank should stand in a stable spot.

Fish may jump when frightened, because of poor water quality or aggressive tankmates, and some species such as hatchetfish or killifish jump by nature. A tight-fitting lid is the simplest protection.

Many fish learn to associate a person with food and swim to the glass when their owner approaches. Some, such as cichlids or goldfish, get used to people fairly quickly and become less skittish.

Fish have no eyelids, but they rest: they slow down, sink towards the bottom or hide among plants. For fish to rest, the tank needs a regular day and night rhythm.

In new surroundings fish often hide for a few days until they settle in. If the hiding goes on, check the water, the tankmates’ behaviour and whether there are enough plants and hiding places; shoaling fish are bolder in a larger group.

Choose nutrient-rich substrate or ordinary substrate with fertiliser tabs, lighting that suits plants, and start with plenty of fast-growing plants. They will compete with algae while the tank settles.

No, an aquarium does not need to be stripped down regularly. Small changes such as trimming plants or rearranging decor are fine, but a complete clean-out destroys the beneficial bacteria.

Before putting the tank in place, fill it and leave it on the floor for a few hours or a day to spot leaks. Protect the seams from sharp objects and only place the tank on a level surface.

Switch off the electrical equipment, move the fish to buckets of tank water and lower the water level below the leak. A small leak can sometimes be repaired with aquarium silicone, but only once the seam is dry and clean.

Use special aquarium silicone without anti-mould additives, since these additives are toxic to fish. Before refilling, leave the repaired tank to cure for as long as the manufacturer states.

Most cichlids need a roomier tank than small tetras, as they grow bigger and defend territories. Dwarf cichlids may manage with 60 litres, while angelfish, Malawi or larger species are often recommended 150–200 litres or more.

Angelfish have tall bodies and long fins, so they suit a tank at least 45–50 cm high. Once grown, they may hunt very small fish such as neons.

The tank should stand where you can easily reach it from the front and top, with room nearby for buckets and a hose. Also consider whether the floor in that spot can bear the weight of the filled tank.

An open or warm tank evaporates quite a lot of water and raises humidity a little. A lid reduces evaporation considerably, and a room with a large tank is worth airing regularly.

Choose active, well-fed fish with spread fins and no white spots, film, sores or swollen belly. Avoid buying from a tank with dead or sick fish in it, even if the fish you picked looks healthy.

Water turtles often hunt and eat fish, pollute the water heavily and need a basking island with a heat lamp. So turtles are usually given their own aquaterrarium and fish are kept separately.