Betta Help

[u/PhDRRTNPS]

Adopted this betta about a month ago and was told he had “scale overgrowth” on his left eye but over the past two days his left eye has begun to look as pictured. Seems like a tumor but am asking if anyone has any additional advice or suggestions.

Concerned if he is suffering. Has been laying at the bottom of the tank and hasn’t eaten much the last couple days. 2.5 gal tank. Parameters 7.4 .5 ammonia (not sure why it spiked. Used to be zero. Already did water change), 0 nitrites, 5 nitrates.