OHM betta with fin rot: which antibiotic should I use next?

Hi all--

The OHM betta I bought from a breeder in Thailand for a pretty penny has developed a bad case of fin rot. He's eating, swimming normally, no fin clamping, greets me at the tank as per his usual interactive self, but his beautiful flowy fins are disintegrating by the hour; it's just sickening. His 5 gallon Eclipse Hex is fully cycled (0 ammonia, 0 nitrite, less than 20 ppm nitrate) and the temp is at 80. I've tried Maracyn (erythromycin) for 5 days, then Jungle Fungus Clear (nitrofurazone and furazolidone) which has been in for the past two days, and his fins continue to disappear. I did 50% water changes before each different antibiotic. I'd like to try kanamycin, but can't find it. What I can find is Maracyn II (minocycline), tetracycline and triple sulfa.

What should I try next? :help: He's not going to be an OHM for long at this rate...

Thanks, akapaul. I imagine traveling in a bag from Thailand might be a tad stressful, hmm? But he's here now; I can't control what happened to him before his arrival. The fin rot started about a week after he arrived.

He has no signs or symptoms of parasites--normal colored poo, no darting, rubbing, scratching, spots or fuzziness; just disappearing fins. He's the only fish in a 5 gallon, so he's not overcrowded or bullied. His tank is filtered, so the oxygen levels are well beyond what his ilk would suffer in a rice paddy or lily vase. The water quality in his tank is pristine: 0 ammonia, 0 nitrite, < 20 nitrate. I don't mess with my pH and don't plan to start; there's no pH up, pH down or pH sideways additives at our house. He's already been through two 50% water changes this week.

He is fed a varied diet of Hikari betta pellets, thawed frozen bloodworms and super veggie kelp flakes (to help keep him regular), all recently purchased, and is not overfed (a max of 2-3 pellets, 2 bloodworms or two veggie flakes per day).

Bettas are not brackish fish and I am extremely hesitant to add salt to the tank of an obviously stressed freshwater fish. I've read up on the pros and cons of salt, and come down firmly on the "no salt" side in regard to bettas (cichlids, I imagine, are a completely different matter).

Sorry, I'm no fish surgeon--there's no way I could trim his fins myself, even if I wanted to. What I want to do is give him the proper medication to knock out the bacteria at play to give him a chance to heal himself. In short, his stressors are minimal, his water quality is ideal, he's failed two antibiotics and the disappearance of his fins is occurring at a frighteningly rapid rate--it's time to pull out the big guns or there will be no betta left to treat. You think tetracycline might do the trick? (I haven't seen oxytetracycline or chloromycetin locally; do you have a brand name I might look for?)

Thanks palmbreeze. I am trying to arrest this rot before it gets to his body. It is eating away at him so quickly. I really hate to use the salt but if the overwhelming opinion here is pro-salt, then I have some marine salt I use in my brackish tank that I could use to prepare a salt bath (I still would not add salt to his tank).

yourchoice, I have no plants and the snails are in the 55 gallon community tank, not the 5 gallon betta tank. I assure you, the betta is the only inhabitant of the 5 gallon. He has nothing in his tank but the filter, the heater, a SeaChem Ammonia Alert and gravel.

If stress is the major cause of fin rot, wouldn't netting and bathing the betta in salt water be a source of stress? Would the benefits outweigh the risks or not? I don't want to just keep throwing things at this rot hoping something will stick--I want something that WORKS and won't make things worse than they already are for my poor fishie... :sad: