So, I have an extra 2 gallon aquarium laying around from a friend who didn't want it anymore. And I've been reading a lot and most people seem to think you shouldn't keep anything in something that small. But I'm wondering, if an ADF would be ok in one? I've wanted one of them again for such a long time after they are what got me started in fish keeping, but my tanks and fish have always been to big for them, so would this work? I have a filter for the tank, no heater tho.