open mouth like he want to bite sound like -heavy breathing , gasping for air. Can you please tell us if it likes like he trying to rub his body on objects?(gravel ,tank walls etc). Is it looks like he is darting around the tank? I think it might be possibility that he might have flukes or ich. Do you have aquarium salt at home?
What is the temperature in his tank? How much and how often you usually change his water?
If he has those symptoms ( darting, rubbing , gasping for air (open mouth) he might have ich or flukes(parasites)
Do you have a heater in his tank? Usually if it parasites raising the temperature will speed up parasites life cycle. So if you have heater you can gradually raise the temperature about (1-2*in about an hour) to 84*
Now take everything out from his tank. Rinse it very well and let it dry out do not put it back in his tank yet.
Give us update, and if you can i would go buy aquarium salt in case it it parasites and you need to use it. If it really parasites i would also buy medications in case you need it, you always can return them if you don't have to use it.
Salt will dehydrate parasites and also help to fall them so you can remove them manually.
You will need to pre mix 2tsp /gall make sure it dissolve , never put it in the tank directly because you will burn him. You will need to do daily 100% water changes . Make sure when you do 100% water changes you slowly acclimate him. Let us know if you don't know how to acclimate betta to the new water so you don't shock him with drastic temperature.
Also wash and dry out all changing equipment after each use.
Last edited by sunlight; 03-22-2013 at 02:31 PM.