Bettas - am I doing this right?

Question
Hi Megan,

This isn't so much a specific question as a general one, but I hope you can help me out. Basically I just received two bettas about a week ago, as a gift, and I really want to know if I'm treating them properly. I've done a lot of reading up, and have read a lot of different answers to all my questions, so in the midst of my confusion it would really help to have an expert's opinion.

I have two male bettas, both in about one gallon of water each and glass marbles at the bottom. I feed them about four bloodworms a day, two in the morning and two in the evening. I do a water change every three days, about 50-75%, and while doing so put in about half a teaspoon of aquarium salt.

Their water temperature is pretty much okay, as I live in a tropical country, and the water temperature is pretty warm throughout the day.

One of them seems perfectly happy; the other one seems to have developed some fin rot, so every day I put in a couple of drops of a product called Melafix (the instructions say 1 ml per 10 gallons) and have been doing so for about three days.

Basically I just want you to check up on me as a betta owner and point out whether I'm doing anything wrong. Too much water changed? Too little aquarium salt? Too much/too little food? What else can I do for the fin rot?

Thanks a lot, and sorry if this is too much :P  

Answer
There are a couple things you are doing wrong:
-two betta should NEVER be kept in the same tank
-healthy bettas should not have their water changed that often (once to twice a month)

Other than that, you are good. There is medicine you can buy to treat Tail and Fin Rot.