Twitching Puffer

Question
My room mate and I recently purchased a spotted green puffer (about 2 inches long) and as he swims around, he has a twitch. I'm not sure if he's just seeing his reflection and trying to attack (which he will do with the stones at the bottom of the tank sometimes) or if he is actually sick. He has no visible spots or anything and nothing else really seems to be wrong- just the twitch. What could it be?

Answer
Sarah,                                                       There are a couple of types of spotted green puffs.Hopefully you  have the freshwater one. It sounds like he might have a parasite. Is he itching against the rocks at the bottom?You can add some coppersafe.I teaspoon per four gallons. If you have him in a tank don't worry about removing your carbon. It medicates for 30 days. Sometimes parasites take 20 days to get rid of. After do a 30% water change .....Good Luck, Tina