I just did a water change this morning for one of my Betta fish "Loki." I had him for about 6 weeks, did water changes twice a week for a .5 gallon tank and never had problems.
This morning I did a water change with aged and conditioned water. PH is about 7.2 (which I kept consistently throughout the weeks since I've had him) and everything was normal and routine.
But when I placed him in, he immediately began to spaz out, head jerking left to right, and now after 3 hours hes struggling to swim, swimming on his sides and lying on his side on the bowl ground periodically. His color went from deep red to pale pink. Holes in his fins appeared where it was beautiful and full just before the water change.
I took him out, put him in some tap water (I ran out of aged tap water and figured ANY water is better) and now his color returned. But he is still spazzing out and swimming on his side, vertically and now even lying belly up occasionally.
I'm baffled. I have another Betta fish "Imugi" and he is just fine. I used the same exact water for both.
Can someone help me? I'm actually thinking of putting Loki to sleep since he seems to be suffering so badly.