Ive had my danios for about a month now. Lively bunch of 5, never any problems. Now, Ive seen him all day swimming almost vertically near where the filter water comes in. And, It seems like the bottom of him is tinted redder in places more than it has before. Definitely tinted redder than his tankmaters. What could be wrong? He just swims in place for the most part, and moves around the outside parts of the tank. Help?? Thanks a lot guys!