My salivator is small enough to fit in a 10, but he swims so much that I dont think I would go any smaller than a 20g. Hes frisky as hell, and aggressive, so hes constantly patrolling his 30g. Like FatHomer said, really a 10g is only good for a dwarf or two. 3 at max. Put a bunch of plants in there, do a nice light, maybe make the tank a rimless, and you would have one heck of a nice tank with 2-3 fish packed with personality. Funny things about the dwarfs I used to have, their huge eyes always show how curious they are. I put tiny snails in the tank and their eyes would light up like christmas morning watching them slowly creep the glass before they would attack and make a meal of them. Really awesome little fish.