Penguin tetra

Behaviour and habits

The penguin tetra is instantly recognisable: a black line runs along the body and into the lower half of the tail, so the fish appears to swim nose-up. It is a peaceful, undemanding shoaler that hangs in mid-water and is far less timid in a group, though it can be a little nippy if kept in too few. In a group of six or more it drifts calmly and looks its distinctive best.

What to feed, and how often

Micro-pellets, flake and small frozen foods such as daphnia all suit it, and it feeds gently at mid-water. Offer one or two small meals a day, and keep the food small — it is a calm feeder that takes food drifting past rather than rushing for it.

Water changes and maintenance

Change about 25% weekly in soft-to-neutral water, matched closely. It is adaptable but settles best in a mature, stable tank, and it dislikes sudden swings.

Care and how easy it is

An easy beginner tetra; keep a group of six or more for the best behaviour and the most striking black-and-silver colour.

Common health problems

Robust; ich appears only in poor water.

If it gets sick

Keep the water clean, warm and stable, and treat early if spots or clamped fins appear.