Have a new Biorb Halo 30 Litre. Any recommendations whether I keep it cold water or install a heater for tropical? Obviously can't house too many fish, or big ones, but really unsure which direction to go. I'd like something colourful like a nemo but understand the biorb isn't suitable for clownfish. I already have a tropical tank but there's only a few neons and a shrimp in there, which could of course be rehoused to the biorb. A heater would mean more wires which might be unsightly, but i've never had a cold water tank before and unsure whether they're harder to maintain and which fish would be suitable. Thanks, in advance, for any advice.