sorry but I agree with Tre. Although hardy, they are mean little beggars and will need to be removed if adding any other fish. If you want to keep them you will need to remove them add the other fish and then add these back to the tank last. I hope your tank was fully cycled before you added the fish as some lfs will sell you damsels to cycle your tank which is both cruel and not recommended. Please read the stickies at the top and again...... welcome!