You have a very hardy little guy there. The stickies in this forum are full of a lot of good info you might take some time to scan through.
First off, your tank needs at least two water changes a week.. one 50% and one 100%. The 100% should include a rinsing of all decorations and gravel. After a month the ammonia will very very high in a tank that size and he is suffering from ammonia poisoning at the very least. So right now he's going to need a water change.
When you say "Betta Safe water filtration" what is this? Are you using Tetra BettaSafe conditioner with filtered water? What kind of filtered water.. do you mean RO water? This may be another thing we need to fix, but I'll wait for your reply to go further.
You need to get a in tank thermometer. The cheap glass ones with suction cups work nicely. Unless you're keeping him in a room that remains 80F+ year round he also needs a heater. The best kind you can get is an adjustable one like a marineland visitherm with a dial that you can set because the preset cheaper ones tend to overheat, fail and fry fish. Add the thermometer first, see what the temp is. Set the heater several degrees below where the tank water is and very slowly click it up until it comes on. From there you can increase the tank temp one or two degrees an hour and no more than about 5 degrees a day. Only at this point, I would keep it low. Don't let it go over 74 degrees, just for now. Eventually we'll want him 78-79 but I don't want to jump start any potential bacterial infection we're dealing with here.
At this point.. he could have anything and everything. To be honest by the pic it looked like he has septicemia and now that I know about his water quality I'd say that's a distinct possibility.
So no fuzzies.. any sprinkles of salt? If you shine a flashlight does it look like he's dusted in gold or copper color? Those would be parasite infections. If not, I'm going to assume it's all bacterial and ammonia poisoning.
To deal with the ammonia poisoning I'd do a 100% water change right now and rinse everything off. You want to cup him while you're changing it out.. use like a plastic solo cup - something you'll use just for him and never have any soap or anything but pure water touching it. You want the water you put in the tank to be the same temp he's in now - which for him at this point will be room temp. Normally I would premix it in a bucket or gallon jugs (like you buy ro water at the store from) and let it sit in the same room overnight, or stick a thermometer in the running tap to make sure it's the right temp. Then put your conditioner in. If you're using jugs of RO water already then presumably they're already sitting around the room and temp won't be an issue. Acclimate him slowly to the new water by adding a couple tablespoons to his cup every 10 minutes for at least an hour before dumping him back into the 2 gallon bowl.
Also for the ammonia poisoning I would give epsom salts. They need to be pure, 100% with no additives. Make sure they are by checking the ingredients label. They can be found at CVS Pharmacy or in the pharmacy section of most grocery stores. Add 1 tsp per gallon, and predissolve it before adding it to his container. I would have him remain in this for 2 weeks. Any time you make a water change you will need to add more salts. If you do a 50% water change add 50% of the salts in. If you do 100% water change add a full dose.
To treat several possible advanced bacterial infections including possibly septicemia I would get a good internal antibiotic like Kanaplex, Maracyn Plus or Furan 2. They will need to be premixed and diluted for the 2 gallon. Depending on which you can I can help you do this.
Last edited by callistra; 12-21-2012 at 08:56 PM.