I just noticed today, since my betta HATES my desk lamp with a passion and I wasn't able to see it before today, that he has this weird sort of white filmy stuff on his back, accompanied by a defined whitish colored line along the base of his dorsal fin. Any ideas what this could be? The only other sign I've noticed is that he stays toward the bottom more than usual, but he still comes up and plays like always, eats fairly normally, and still bumps into everything when he decides it's play time. He will gently bump into the air tubing or the filter more than anything else and ninja-fly backwards. He doesn't cause himself any damage and he does it multiple times. It's not a sign of whatever this is. He's done it forever. He has an olive nerite snail in with him, and there's two caves to hide in.