Thanks for the warning! When I've had issues with my bettas in the past, I've had good luck with just using a little salt, making sure they get some extra oxygen, and doing partial water changes more frequently. I've also used meds called Melafix and Pimafix in emergency situations on koi and goldfish and had wonderful results. Two years ago I rescued a koi from the pond at a greenhouse I work at, when the koi got its tail eaten off by a faulty filter system, and though he really should not have lived, these two meds seemed to help combat the horrible infections on his wound. Now he is healthy and happy even though he has to wiggle a stump since he has no tail! Good luck with your betta!

I always use 1/2 teaspoon of aquarium salt to my 2.5 gallon tank for my betta, and lo and behold, no problems for him and I've had him for 10 months now.