I've recently transferred our betta into a larger 10 gal tank. He was in a 1.5g tank but did not like the change in temp. He would just lie on the bottom and not eat in old tank, but I knew it was because of the temp change of the water.
I got the new tank, treated it, and got the temp to around 75-78. I slowly acclimated him to the new temp and he seemed to transition fine. Even the addition of 4 Corys didn't change his mood or actions.
After almost a week he still will not eat, he sits at the top of the tank occasionally moves and now is looking VERY pale in his body. Saturday I tried putting a mirror near to get him going, but he just looked at it a bit and did a little backwards swimming. He is going on 2 years old since we got him, so I am not sure he is getting on in life.
Thanks in advance.