This is gonna sound a bit harsh but I think it needs to be said in hopes that others will learn from it. What you are saying is, you bought a fish that the lfs
warned you would get to large for your tank and with a no return policy? I'm sorry but that was very irresponsible. Even without doing your homework, you were aware that the tang was gonna outgrow the tank and was not well suited for your 29ga so you can't blame this on the lfs
. Even if they said it could live there temporarily, you made the decision to buy an inappropriate fish.
Moving the rock around may help temporarily but the damsel will probably end up stressing the tang to the point of no return. It's what they do. They are aggressive and in such a small tank with being already established in that tank, I doubt moving the rock will be a long term fix. Again, I'm sorry if this sounds harsh but it's up to us to do the best thing for our charges. It's up to us to show restraint and be realistic and responsible with our purchases. Buying something like a clown tang, (or any fish really) that you know nothing about just because it was the only small one there, with warnings from said lfs
that it will outgrow the tank eventually is just bad fishkeeping. What were you planning to do with it if you can't return it? Do the right thing for this fish. The tang needs to be returned or given to someone with a system to support it. Clown tangs aren't the easiest of fish to keep even in a proper system. There has to be a lfs
that will take it. You may not get a refund or store credit but I don't know many lfs
that won't take a free healthy fish. Chalk this up to a learning experience and carry this with you when you purchase your next fish. Hopefully it will help you to make better decisions in the future. With damsels in the tank already established, adding other fish is always going to be risky. Perhaps the addition of some ornamental inverts would be a good idea instead. Good luck.