I just bought 3 neon tetras. Ive had them for about 4 days now but I noticed that one of them looked as if his lower jaw was bigger than the others. I looked closer and noticed what looked like a round "zit". As you, know, neon tetras are small, timid and fast and its hard to get a close look but it looks like a tiny zit. It doesnt appear to bother it nor disrupt its eating but should I be worried about this? thank you?