Ask a grown-up: what do fish do all day?  

Alex Cliffe, aquarist at London Zoo, answers three-year-old Elsa's question

Here at London Zoo, we encourage the fish to behave like they would in the wild. The lights go on as the sun rises, and this lets the fish know it's breakfast time. Each fish gets food especially for them – some eat plankton and fruit flies, others eat seeds and vegetables; some fish hunt for their food, others forage for it.

Once they've eaten, fish spend their days guarding their homes, and at this time of year, breeding season, they spend lots of time competing for mates. The males try to impress the females, and the females carefully decide on a mate – the female seahorses even do dances with the males they like. Then the fish will lay eggs or give birth, and some of them then spend a lot of their time looking after their offspring.

When the lights go off and the sun sets, the fish pick a sheltered spot and rest for the night. They don't really sleep, but they relax before another busy day begins.

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