thanks for the info. I will look into low light plants for it. So the large water change caused this hmmm intresting. Deffintly alot different than a salt water tank. But the betta still seems to be fine even if he dont get any tank mates. What I might do is set up my 30 gal with a couple otos. Then when they are settled I will move the betta over. Might help them get along.