OK, I got a question or 2… (I am new to owning a Betta)
Maxx (my Betta), is in a 3 Gal tank with a Bio-Wheel type filter as well as a heater and a few plastic plants. Betta Maxx gets fed mostly Betta flakes as well as some freeze (dried?) blood worms. He shared the tank with a Ghost Shrimp (HC a.k.a. Head Cleaner - to help keep the tank clean) for a while and then ate him (R.I.P. HC). Then I bought 3 more Ghost Shrimp (Shark Bait, Ghost Face Killa, and Mr. Ghosty). About 1-1/2 weeks ago he ate another Ghost Shrimp and his belly was BIG & his scales kind of stuck out (like Dropsy). He kind of laid around like Al Bundy on the couch with his hand in his pants until he finally started digesting the GS and his stomach is almost back to normal, but the other day I noticed a small spot on one of his side (up towards his belly) that looked like he had lost a few scales and kind of white in color. He seems to be swimming more then when he was working on digesting the GS, but not as much as before. I got some stuff from my local pet store to help heal him last night to put into his water (sorry I forgot the name of it), but the more I read on here today, I am wondering if a salt bath would be a better approach. Or should I take him out of his tank & use the medicine in a different tank with him (and fully change the water in the big tank).
Also, I have noticed that there are some places on the fake plants and on the side of the tank that turn brownish in color. I cleaned the tank & the plants with HOT water (not detergents) when I did a water change and in about a week those brown areas are returning… but not in the same spots.
The brown spots are algae growing on the plants I think. How long do you leave the light on? I'd stick to salt baths IMHO. If that doesn't help, then try treating with medications. It's always better to treat them with a non-medicinal way if possible - it is much less stressful on them. Welcome to FishForum and good luck!
Basically just keep a consistent temperature between like 76-84 degrees F. Fish go into shock when the temperature is vastly different from what they were in before, if you want to adjust them slowly, put them in like a plastic cup and float them in the water you want to stick them in for a little while.