Fish mox= amoxicillin

While technically it could work I am highly against it for 2 reasons.  1 being antibiotics aren't just something you leave sitting around in your medicine cabinet to use when you feel like it.  This is not aspirin.  There are consequences, side effects, and they need to be matched up to the problem.  Over use of antibiotics is causing strains of bacteria that will not be killed by any of the commonly used antibiotics.  Different bacteria also respond better to different antibiotics.  If you just guess and start taking one you may end up creating a resistent bacteria that requires alot more work and expensive antibiotics to clear up.  I know someone that spent 6months and over $1000 on a guinea pig to clear up what started out as a simple infection but because of that they used a weak antibiotic and the bacteria did not respond.  By the time they worked their way up to a really strong antibiotic the infection was systemic and the bacteria had become resistent to all but the strongest meds.  It also happens frequently with horses where owners give them otc penicillin for any little thing and what starts as a small infection turns major because the bacteria have become resistent and can't be killed.
 
2nd reason.  Do you know the safe dosage, how to calculate it, possible side effects, and proper use of the medication?  You can't just grab a bottle, read the fish dose, and give it to the dog.  You need to be able to weigh your dog(easy for small dogs but those with large dogs are likely to guess) and then figure an appropriate dose based on mg/kg or mg/lbs.  How many mg/kg is safe and how many kg does your dog weigh(exactly not about this much or as of last vet visit months ago...).  Do you know when antibiotics are necessary and when they aren't?  Giving them antibiotics just because they have a fever or a small cut is likely to lead to at least a few headaches and uncomfortable days for the dog but possibly a life threatening situation if everything goes wrong.
 
It's much easier and much safer to take your dog to the vet and they will have no problem giving you these medications or something more effective if that's what's needed.  They aren't really that much more expensive from a vet than getting the otc fish meds.  In fact if you really want to save every penny possible you can request the vet write out and give you the prescription and then go online and find a cheaper source for the meds.  Fax them the prescription and they'll ship it to you.  Trying to diagnose and treat yourself is a bad way to go if you have no vet training or a heck of alot of experience doing it.

Woah!   Hold on there killer.  Lol. I didn't say anything about diagnosing and treating a condition on my own nor did I suggest that it be taken for every sniffle that comes along.
Sometime I think that my common sense is similar to others but I forget that 's not true.
 
I'm pretty sure you are addressing the very unknowledgable/irresponsible when it comes to  pets' health and needs.  Or at least it is sounding like it. []  good points to bring up by the way.
 
Ok, let me ask it this way:  "If your vet has dispensed to you amoxicillin for an infection that your pet has developed whether it be skin, ears or even the common cold like so many vets do (as often as they do I might add)....and you have run out but need to continue the course for another week per your vet, would you:
A) Pick up another 28 pills of 250mg amoxicillin for $30.00 from the vet
B) Pick up a bottle of 30 pills of 250mg amoxicillin for $12.50 under the name Fish mox?
Given it is the identical stuff?
 
No lectures please...just curious. [] 
 

For $15 extra why not get it from the vet?  Then there's no question the quality or dosage and if you can't scrape up $15 then your probably on the verge of not being able to take care of the animal at all.  Oftentimes off brand or meds used on a different species are not as strict on the actual mg they contain.  In fact I had a doctor that would occasionally make me get the name brand stuff even if it cost several $100 more because the generic is not always as accurate.  The dosage of each pill can be off by a small amount which is actually allowed by the FDA and doesn't usually cause problems.  Now consider how lax they are about the treatment of fish(hardly any laws at all) and I'm not sure I want to find out how accurate fish meds are just to save a few bucks.  If we're talking in the hundreds of dollars and for some reason I suddenly don't have the money so I either take the risk or don't treat the animal at all then I'd do something like that.  In most cases I'm more than willing to diagnose and treat most injury and illness myself and I do know how to calculate exact dosages from a specific weight but in this case the potential risk well outweighs the cost.  I treat my guinea pigs mostly myself because I have done more research into safe meds and dosages than most vets and the only vet I do use I basically just say I need so much of this and they give it to me.  I'll even tell them how I want it compounded but even with that much experience I'm not gonna mess around with an antibiotic that I can't accurately measure what's in it myself.
 
If people see they can get meds cheap without going to the vet alot of them are gonna take up the offer.  Especially the ones that don't know what they are doing.  I've dealt with alot of people where it was near impossible to get them to take an animal to the vet in the first place.  They are often even willing to just let it die.  If they think some fish med they can buy at the nearby petstore is going to help they'll start dosing everything they can get their hands on just to avoid a vet bill.  Bad situation to start.