Most aquaponic gardeners aim to practice growing organic crops, and this includes making sure the fish are not given growth hormones. Instead, the fish are fed a natural diet composed mostly of fishmeal and fish oil, which can also ensure high levels of Omega-3.
When it comes to treating fish diseases, antibiotic use is prohibited. Since much of the system relies on the conversion of ammonia and nitrites to plant food, bacteria need to thrive. In that case, administering antibiotics is actually counterproductive and might disrupt the overall system. The most common method of treating diseased fish is to isolate them in a separate tank and apply a salt bath solution.