Good topic BennyMG1.
I have not had to use any fish antibiotics yet, so I cannot speak to efficacy, but I have some. I bought various fish antibiotics from two different sources within the past two years. No prescription needed. I also found several sources for the human variety from online US providers, but they are not anonymous, provide limited amounts by comparison, and are much more expensive.
Were the vet pills visibly identical to the prescribed human ones?
In today's society, where all the help you need for just about anything is instantly available with a 3-digit call, most people do not seem to see the need for stocking expensive antibiotics at home. There is also a steep learning curve, so you will know how much of what medication to use and how long to use it on a given injury or ailment. I am guessing that for most people, that is too much work.
In the past couple of years, I have needed to use "excess" antibiotics that I had on hand to treat sudden medical issues, either because of timing, as the issue became apparent at the beginning of a long weekend, and I did not want to go to the ER. Once, the pharmacy could not get the specific, commonly prescribed antibiotic for three to four days, which is scary in and of itself, but fortunately, I had some on hand. Having a stock of the appropriate medication immediately available at home can be a lifesaver in some situations.