So what exactly are you doing? JFE and salt, right?
I would not use BettaFix in this situation for multiple reasons; the first being that it contains melaleuca, which has been shown to irritate the labyrinth organ in anabantoids including bettas. The other is that bettafix is a healing agent and an antiseptic, it is not an antibiotic. It is the aquatic equivalent of putting peroxide on a cut. If the fish has a systemic infection, it won't help at all.
Also keep in mind that bettafix/melafix works because it is an irritant--the irritation it causes around the wound site increases bloodflow to the area, stimulating more rapid healing. This works very well for goldfish, but I would never use it on a betta.
About the white poop question--I have found that mucusy white or stringy poo along with a distended belly and loss of appetite are definite signs of internal parasites. Keep in mind that praziquantel medications are not the same as antibiotics, and though they shouldn't be used recklessly, they tend to be much less harsh on fish, and overuse of them has a much less profound effect compared to the overuse of antibiotics.
It is good to hear that he is doing better--please keep us updated.
Last edited by Adastra; 07-13-2010 at 02:08 PM.