Corydoras

Behaviour and habits

Sociable bottom-sifters that grub through the substrate in loose groups and surface to gulp air. A lone cory is a nervous cory; a group of six or more behaves completely differently.

What to feed, and how often

Omnivores that find food by sifting and smell, corys do best on sinking pellets or tablets, backed up with frozen bloodworm or daphnia and the odd blanched vegetable. Feed once or twice a day and drop it near the group, or the faster top-dwellers will eat it first.

Water changes and maintenance

A weekly 25% change suits a bottom-sifter, since they are the fish most affected by dirt in the substrate. Vacuum gently over the surface rather than deep into it, and keep the water clean and well oxygenated.

Care and how easy it is

Easy and peaceful; keep them on soft, rounded sand to protect their barbels, in a group.

Lifespan

With good conditions and steady water quality, this species typically lives around 5–10 years in a home aquarium; some individuals live longer.

Common health problems

Prone to barbel erosion on rough gravel and to fin rot in dirty water.

If it gets sick

Watch the barbels — short, grey or worn whiskers mean rough gravel or dirty water. For fin rot, fix the water and substrate first, then treat, observing for a few days.