If you are looking for something to give him for stress you can use Bach Rescue Remedy, the liquid form. There is no recommended dosage for a fish/tank but I wouldn't use more than a few drops simply because it shouldn't be necessary. It effects different animals on varying levels, some you will see obvious relaxation immediately, others no apparent effect... as for the stress coat I have a blue tang he has had ick very bad and he has always been very aggressive , thought it would keep him calm,worried he all get it again,but if you say not to use I will it rid of it