Koi

Ben Helm says...

Koi make such good pond fish because they have many favourable attributes – they thrive in still water, are tolerant of a wide range of temperatures and water qualities, and perform well on artificial diets. They are opportunistic feeders that graze rather than hunt and this non-predatory nature is born out by their non-territorial behaviour. In fact, it has been shown that Koi are gregarious, preferring the security of shoaling in numbers.

Ben used to farm Koi for a living and has published three books on ponds. See his website watergardenersbible.co.uk for more details.