We added a pair of percula clownfish to our tank one week ago. This is a new tank, two weeks old, and these are the first fish in the tank. They seem to be doing well except for a strange looking twitch from the smaller one. He's about an inch long, seems active and is eating well. Occasionally, the little one will go into this state where it looks like he's being shocked for one to three seconds, then he goes about his business. Normally, these convulsions seem to be triggered when the little fish bumps into the larger fish. The twitch has been going on since day one. Anybody seen something like this or know what it might be? Thanks for the help.