I bought a betta a while ago (maybe 2 months) and he had fin rot and Velvet when I got him. I treated with malachite green and formaldehyde and it cleared the velvet up and his fins really started to repair but after 2-3 weeks just when his fins were really getting some decent regrowth he got a spit in his caudal and he continued to get more spits and his tail began to break away so I treated him with multi cure and again he seemed to be cured and his fins began to regrow..... a couple of weeks later more tears and breakage so I treated with triple sulfa and again they began to get some decent regrowth.
I then bought another betta and he was breathing fast when I bought him but I thought he was just stressed, he also had two small tears in his caudal but they looked like old injuries as there was definite regrowth. Within 24 hours I noticed that he had lots and lots of tiny little tears that were about 1mm apart and they would stay like that for a day and then break away and new tears would form so I treated him with triple sulfa and his fins looked like they had new regrowth so I put him back in the barracks tank yesterday and in less than 24 hours he had those tiny splits 1mm apart again and the other betta (mentioned above) had new fin damage as well!!!!
The weird thing is that it does not seem to be contagious as they were sharing the barrack with 8 other bettas for about a month and they are all fine. The two bettas with the finrot have no red or black marks on their fins in fact other than the fact they are breaking away they look completely normal. They are also healthy and active and eating well. They are in filtered heated tanks that are cleaned a couple of times a week 50% changes and they are in about 3 gallons each within the barrack tank.
If anyone has any treatment suggestions I am open to all recommendations, this fin rot is very persistent and despite treatment they keep having relapses I just can't seem to permanently get rid of it!!! Keep in mind I live in AUSTRALIA and cannot get access to Mardel products (I contacted customs and they said I would have trouble getting any fish medication through customs). Please help, I have read all the stickys and have dealt with fin rot many times successfully but this time it is different it just won't go!!!!!!!
I am going to town tomorrow so I can get meds then and I think I'll buy some quarantine tanks to make treatment easier.
I can't really get photos at the moment sorry, my batteries are flat.