hm..he wouldn't actually fit in a 5 gallon..i have him right now in a 30-40 gallon tub with an airstone...I added some salt and pondcare melafix, but now he's gasping and floating on his side. can i save him??
Ah sorry i didn't realize how large he was. Anyways, this is what i would do in your situation;
1. The carp will be producing a lot of ammonia in its waste on a daily basis and this will be doing nothing good to help his condition, so i would advise doing at least a 50% water change per day to try and keep ammonia levels down. Make sure that when you fill the tub back up, you try and match the temperature of the new water as close as possible to the existing water in the tub- if you are finding it a little difficult to match the water temps, its better to have the water a little colder rather than a little warmer. Fresh clean water is often the key to recovery in fish
.
2. The airstone will be helping a little bit when it comes to oxygenating the water but they are not that great for oxygenating water- a proper stronger filter would be better for helping improve oxygen levels (the carp is most likely gasping right now due to a lack of oxygen in the water).
3. Melafix is so-so for bacterial infections, Pimafix is a bit better though- personally i have used "Anti internal bacteria" by Interpet coupled with Pimafix with a lot of success when it comes to treating external/internal bacterial infections in general
.
4. Try and cut back on the amount of dried foods the fish is being fed as these make the fish poop more waste (you want to avoid ammonia levels increasing as much as possible)- frozen foods like bloodworms, krill, artemecia etc (except tubifex) are more nutritious to feed fish and don't create quite as much waste. Just thaw a cube of food out and give the fish a pinch of it first to see how much it eats of it (you don't want to have any excess food lying around in the tub and sick fish don't always have that much appetite etc).
5. Make sure the tub is in a quiet dark area- putting a damp towel or board over part of the tub to make it darker will help calm the fish and make it feel more secure (its fine to deprive fish of light if its only for a few weeks or so). Putting a plant or large stone in the tub will help give it something to focus on and help make it feel more at home etc- basically by reducing its stress levels as much as possible you'll help improve its chances of recovery
.