What antibiotics can be used if a fish has like a large chunk missing from it like if a fish suffered a bite. Would any antibiotic like the ones for people work?would adding that to the water or the fishes food be able to save it?
I don't know but are you going to do the surgery?
Nitrofurazone will work and is found at Walmart for 4 dollars. Called jungle's "fungus cure"
I didn't think to put in about it killing the cycle because I figured when I said dip or bath it would mean in a separate container and not dosed directly to the tank.I don't really think there is any need to. And as the other person should have warned you, methylene blue will kill all your biological bacteria filtration, while furan green won't harm anything. Methylene is very messy too, stains on anything fabric WILL NOT come off.
The way I use Methylene Blue is 2 ways depending on injury. A mild injury like a few missing scales or torn fins, I would just do a light dip like 1 drop per gallon. A more deeper injury like decorations injury or fighting with bite wounds I would do 2 to 3 drops per gallon. For deeper wounds such as deep holes in the body I would do up to 5 drops per gallon dip for 10 seconds then direct application of Methylene Blue to the wound at least twice a day. It really depends on the injury on how I would work with it.
Also I would not mix paraguard with blue dips, though there should not be any drug interactions, over medicating is not a good thing.
Methylene Blue is a rather safe product. It has multiple uses such as elevate Osmotic Shock, PH shock, Ammonia Poisoning and is a brod spectrum antibacterial, fungual, antiparasitic treatment. Because it is safe to use when done right (dips, baths, and direct application) I highly recommend the use of it. It takes 10X the dose before it becomes toxic to fish as well.
Malachite Green (which is in Paraguard) is milder then Methylene Blue, but does the same things. Just can be slower.
At the other end of the spectrum is potassium Permanganate. This is the strongest one. You must follow the directions with it because it becomes toxic at I believe 2X the recommended dose.
Like I said, I prefer Methylene Blue. I have used it for years.
If your going to actually do cutting, you should swab the wound with potassium permanganate(PP) and keep him in a small hospital tank with Methylene blue(MB) double dosage. Use gloves when using PP as it will absorb through your skin. If you overdose with PP, apply Seachem Prime to neutralize it. You will have to change the water in the hospital tank 100% daily because there is no way to maintain a biological cycle in the conditions. With that said, I suggest not having a filter on the tank at all but you should have an air stone. MB promotes oxygen exchange in the cells increase the heal rate of the fish, so the more you agitate the better.
Malachite Green is actually stronger than MB, but not as good of an antibacterial. It is best used with parasitic infections which is why you find it in most ICK and parasite meds under multiple names. It is toxic to fish and humans, the toxicity increases with the temperature and it builds up in the kidneys and liver of the fish. It also permanently stains silicon and other plastics, decorations... but will not harm your archaea in your filter. MB and MG are dyes that have been found to have medicinal purposes, it should be kept in mind when using them. The good news is that because they are common dyes they can be found cheap online, MB can be bought as a powder (Zinc free) added to water as needed.