Provided that the tank is cycled and Looking at the parameters I like to keep ammonia at 0 and nitrates under 20 , salinity between 1.024 and 1.026 . I have a mixed reef tank with a kole tang and a naso tang which do very well . Haven’t lost a fish in many years except when one jumped out in the middle of the night .any trace of ammonia I would take action to get it to zero with water change and bacteria used to help cycle the tank , I would first wait til ammonia is zero . Make sure you have enough bio material to handle the bio load , then enter the fish one at a time to make sure the tanks bacteria bed can handle the extra load and expand before adding the second . My naso tang eats nori , pellet , flake , and a assortment frozen foods such as fish eggs and mysis shrimp . When you do add a new fish , quarantine and make sure it’s clean and healthy before you add it to the show tank . Cleaner shrimp helps to . Just try to keep your perimeters steady and as far as oxygen I only run a skimmer and do water changes . Hope this helps