Tanks & Bowls

It is tempting to think a small tank is easier to look after, but the opposite is true. A larger volume of water buffers swings in temperature and chemistry and is far more forgiving of mistakes. For a first aquarium, a 60–100 litre set-up is the most balanced start; kits that include filter, heater and lighting make set-up straightforward.

Bowls may look decorative, but they do not suit most fish. Goldfish grow up to 20 cm and produce a lot of waste; even a single goldfish needs 60 litres or more. Bettas need at least 20 litres with a heater and filter. Ammonia builds up quickly in an unfiltered bowl.

Set-up and cycling

Do not add fish to a new tank straight away. Treat the water with dechlorinator, run the filter and add a bacterial starter. The ammonia → nitrite → nitrate cycle usually takes 3–6 weeks to establish. Measure levels with a test kit; once ammonia and nitrite read zero, add fish gradually, a few at a time.

Place the tank on a level, sturdy cabinet that can take the weight (100 litres of water plus gravel is around 130 kg). Spots in direct sunlight lead to algae blooms. Limiting lighting to 8–10 hours a day on a timer also makes algae much easier to control.