Having wanted an indoor aquarium for ages, I finally splashed out (haHA!) and bought a 28L tank, with a cartridge-type filter. With memories of fish-keeping from decades back, I had a notion of getting two or three small goldfish for it.
But I've been reading around online, and the message seems to be: Do NOT put goldfish in a tank that small!
So.... What fish can
I put in it? I really don't want to use a heater or light (I'm in the south-west UK). I do like the idea of minnows, but they seem to be even more complicated to keep than goldfish.
Suggestions and/or advice, please!