*nods* Yup. They're tropical fish. They CAN live in the smaller containers, but a bigger one is better so they can actually swim around and "stretch their fins"....kinda like a dog is fine living in an apartment - its basic needs are met, but they deserve to go for long walks and have a yard to run in.
:)

For the size container you've got 'em in, you should be changing about half the water every week, unless you've got an test kits of ammonia, nitrite, and nitrate and test the water regularly to make sure everything is under its limit. I'm totally not meaning that to sound snotty in ANY way, and if it at all comes across like that, I totally apologize. I just love the little boogers and want the best for 'em.