Originally Posted by freshwaterfishies
Recently my Betta started to act strangely, it started a few days ago when i added an air stone to his home. He started to swim frantically and was rubbing against the few stones that are at the bottom of his tank, so we moved the air stone up and to the side (from the middle.) this seamed to help at first, but now he just kinda sits at the bottom of the tank and mopes about. Once in a while he will get up and swim around normally. He still rubs against the rocks from time to time. Two days later (after adding air stone) he ate some of my ghost shrimp that i had in there with him and now his belly is sticking out.
just fast him a few days, and if he is scratching himself against things he might have internal or external parasites like ich or velvet.
Ich is recognizable if the fish has white little spots like if you put salt on him.
Velvet: will cause the fish to act differently than a healthy betta fish. They will be less active, have less vibrant colors, lose their appetite, and sometimes be seen rubbing up against objects in their tank. Betta fish with velvet will have what looks like a gold or rust colored dusting on their fins. This can sometimes be hard to spot and can be made easier by shining a flashlight on the betta's body. (quote from yahoo)
Both are contagious so pull them out if they are sharing tank with other fish and quarintine them. Sanatize their main tanks, with boiling water and rinsing with vinegar or watered down bleach without detergent till the smell is gone.
Treat them with anti-parasital medicine, you also may want to treat the main tank, just make sure the fish you have there won't be hurt by the treatment.