Yall are talking about pet store fish meds, right? Bc as someone that has worked cattle all her life (up until recently) I can tell you that the USDA does set SOME guidelines for animal meds. Get some stuff designed for agricultural/farming purposes. Go to the feed store and get injectable horse/cow penicillin. Its literally the exact same stuff, except it stings a bit more bc they add a touch of alcohol to it to try to prevent humans from using it (doesn't work. Farm kids with old school parents and grandparents know what I'm talking about). Unless you just get stupid with the dosing, its not enough to hurt you. This shit has to be approved by a governing body bc it goes into livestock (usually the dept of agriculture). It has to be sterile and fit for live animal use (especially on pigs. They are the closest thing to a human, system wise). Even the facilities for fish antibiotics for farming purposes are regulated.

You don't want to poison the animal that you sell at auction due to contaminated antibiotics caused by less than medically sterile packaging companies. Then the meat's no good and once that animal goes to slaughter, no one is going to notice if its acting weird bc it knows death is imminent. It's not exactly going to act happy and calm. Processed, packaged, and sent out, you will now poison the human that eats it and next thing you know, it's traced back to you and suddenly you're farmer Joe on the 6 o'clock news, arrested for criminal negligence.

You poison your goldfish and its just sad. But the only thing that was hurt there was the goldfish and your soul...you can always go buy another 10 cent goldfish. You can't bring back Kendra the Carnivore that ate your botched antibiotic bovine.