please help me understand what happened to my betta. i had him for a couple of weeks. in the beginning he was quite mopy and non-interactive, wouldn't flare. as i learned how to regulate his water temperature and feeding he became very strong, colors brightened, showed fishy intelligence, followed me around the room with his eyes, and even blew a bubble nest. i decided to add a tankmate: an african dwarf frog and apple snail from petsmart. the frog we chose seemed healthy when we got it. i didn't notice anything wrong but i don't think i looked close enough. i sat the bags of the two new animals in the betta's bowl with him for about two hours. betta seemed curious and swam all around the bags. i emptied the new animal's bags water and all into the betta's bowl. then i noticed one of the frog's feet was white and the toes were curled up as if the foot was dead. he could still get around fine and i had heard of frogs regenerating limbs so i thought i'd just keep an eye on him. the betta nipped at him a couple times but not very aggressively, just like, what's that? the betta acted normal for a while but gradually started to avoid the frog rather than follow it.
over the next few hours the frog's behaviour degenerated until he was staying near the top taking frequent breaths, and getting himself turned on his back somehow. eventually i saw him dead at the bottom. this was all in just a few hours. another hour or so later i noticed the betta not looking so good. i took the water temperature and realized, oh shoot, it is 69 degrees and he hadn't been that cold before-he had been at 71 degrees for a long time though and then he just stood still at the bottom. instead he started hanging around near the top like the frog did taking frequent breaths. his mouth/eyes area became very pale and almost puffy looking. to me it seemed like the color going out of his flesh, as it followed the pattern of his scale if you know what i mean-not something on the surface though i think he was producing mucus or something. he kept sticking his nose out of the water and looking up at the light i have above his tank, like he was trying to...lol..go towards the light x.x poor thing. i added a tsp of non-iodized salt to the 5 gallon tank and went to sleep for the night. the salt seemed to perk him up as far as i could tell at the time, i hoped it would solve the problem if it was fungal/bacterial. in the morning he was dead.
i want to know what happened so maybe i can prevent it in the future. shock from the new water? disease from the frog? too low temperature? it seems too weird how the frog went the same way the betta did, and the foot thing.. maybe it was just shock from the mixing environments idk. the snail is just fine.