I've probably mentioned before that my almost 2 year old boy likes to play in the fishtank occasionally. Well, occasionally has turned into several times a day. He doesn't seem to be able to get the fish (thank god), but he will sit on the top of the fishtank and (he's doing it right now!) he will look down in the little hole between the cover and the filter, and then stick his paw way down almost to the bottom. Then he licks his paw and for some reason it always make him sneeze. Now, the condition of my fishtank is what I like to call "natural" and "pond-like". It has a lot of algae growing in it, and despite my cleaning efforts, it always comes back pretty quickly. But anyway, my question is, could the algae be bad for the cat if he gets some on his paw and then licks it?? and not to mention that it's probably throwing off the ph of the fishtank to have his paw in there all the time...but that's another issue. what can i do to keep him out of it?? behavior modification doesn't seem to work with him, and i've tried putting duct tape over the holes in the fishtank cover, and he just peels it off! any ideas?? thanks!