I got a clownfish on Friday and everything has been going really well with him so far.. he's eating, moving around a lot, getting along with the other 2 fish... When I got home from work today I noticed that he has a clear/cloudyish what looks like a bubble on one of his eyes (the bubble is small). He's acting normally though, just ate.. I was planning on doing a 20% water change tomorrow, do you think the problem could be old water? And how do I fix his eye? I don't want to wait too long before I do anything.