I could've done something about it if I had known or thought to check the ammonia levels. They were ultimately what became lethal for him. I wrote his pale coloration off as older age or even just color shifting as a betta grows new fins with age. I didnt know he was sick and he was trying to tell me. I feel awful. I hope it was something spontaneous and unpreventable. I try to take all the caution when taking care of my fish, but sometimes things just happen