I have a friend who just got a betta - I think that it's one of those situations where someone gets a betta in a little minI fish prison jar (grrrr) and moves it into a larger jar full of tap water with no one telling the person anything about fish. I could be wrong, and will find out, but regardless, it raised this question for me. I have an established healthy tank. Could I do a water change on my tank, putting the water into an uncycled tank (like I suspect this betta is now in) in order to jump start that tank having healthy water? I understand that one might run a risk if one's tank had any sort of disease, but if everything is testing well and fish all seem healthy, would this be a better risk to take than keeping a fish in an uncycled tank?