Hello. I have a male betta, that we got 18 months ago. He shares a 2.5 gallon tank with a mesh divider with a female (he wouldn't let her eat without it). All was well until the last tank clean about 2 weeks ago.
I have a container of fresh water that I keep next to the tank and I add some daily to keep things fresh in between changes.
He stopped making bubbles, and the last few days was not eating eagerly as he had been.
Today I notice he is starting to curl his body sideways, and is leaning against the side of the tank, still at the top.
There is a little pad-style heater in the tanks that I have used all winter.
I am afraid changing the water now might be too much of a shock.
Any suggestions? PS the female seems just fine.