dwarfgourami
Fish Connoisseur
It is about other needs as much as filtration. Personally, I would not have a great problem with putting a bristlenose in a 20 gallon tank, and indeed this has come up several times on the forum without any flaming- but I would be less willing to do the same thing to a restlessly active red-tail shark. In fact, I'd rather stick the bristlie in there than the comparatively tiny, non-messy but hyperactive portholes. You can always up filtration but how can you comfort a fish whose need for activity is not being met?
