I bought a regal tang a few days ago, but ever since its been in my tank it rubs its side against the live rock as if it has some kind if irritation. it does this about 3 times then goes and hides behind the live rock I have in my tank. The tang doesn't have any signs of ich (white spots etc).

I have 3 regal damsels, 1 behn's damsel and 2 clown fish in the tank all of which seem fine. Iv read this can be down to the fish getting used to new environment, but the fish its doing this all day long! Having said that its only been 3 days since I got it. Nitrite is a little high but is on its way down. salt was low but iv fixed that today.

Any help is appreciated. Many thank in advance.

Fish scratching the rocks is definitely a sign of irritation. Unless you are prepared to remove and quarantine the fish, you are pretty much left to watch and hope for the best.

You may wish to do a partial water change. This will help in reducing nitrites as well. Good luck.

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Doc

Dr Hank's 200 gallon Reef Tank
http://www.aquariumforum.com/f46/drhanks-tank-3440.html