it definately sounds like the betta is stressed.
does he look bloated at all?
also, be careful with the heater. it may be very difficult to find a heater for a tanks that small, but I believe some companies are making 15 and 25 watt mini heaters out there that would be a good choice.
just be careful, a small tank volume can heat up very fast.
bettas don't mind being at room temperature, the water in their native habitat can get cool at night.
does he look bloated at all?
also, be careful with the heater. it may be very difficult to find a heater for a tanks that small, but I believe some companies are making 15 and 25 watt mini heaters out there that would be a good choice.
just be careful, a small tank volume can heat up very fast.
bettas don't mind being at room temperature, the water in their native habitat can get cool at night.