I'd suspect that those antibiotics, eye meds and ear meds are refills, not initial prescriptions. If they are initial, original prescriptions then that vet is almost guaranteed to be breaking at least one law and/or guideline set out by their governing body and deserves to be reprimanded, at least! Merry-go-Medication is a very dangerous game to play. Our clinic has seen fish- especially elderly koi and saltwater fish. Though, arguably, we generally do a home visit since so much of fish medicine is preventative measures and husbandry issues. Unless they require surgery, then they have to come to our clinic as surgery suites are a little hard to move. I have to admit we've never seen a seahorse, though- usually they die before anyone can call us, poor delicate things.
I'm glad your snake is doing well!It's definitely helpful to have someone "in the know" whether it's a vet clinic or a human clinic.