i've had my betta for about 5/6 months now, with a congo frog and zebra nerite snail in a 6 gallon tank. the tank is heated, at 25 degrees, but not filtered. anyway, he used to move around almost constantly, and used to stay at the top of the tank and eat all his pellets. recently, however he's not eating anything, he looks fine, but he's not swimming around much anymore. he's still coming up for air, and for a little while he didn't flare, but now he does again. is there a problem? what can i do?
thanks in advance.