Hello,
I am new to this forum and am in need of help

I am raising about 30 western toad tadpoles. Ive been doing so for about 3-4 weeks. Ive been feeding them romaine lettuce that is first boiled then frozen. Recently ive added HBH frog and tadpole bites in there as well. It seems when I added that they ate the lettuce much less A few days a go some of the tadpoles made it to froglet stage. They seemed regular they'd swim sometimes and sit on a rock that is in the tank sometimes. But today I found one dead just floating in the tank. Then three hours later another one was dead in the tank

I am wondering what could cause a seemingly healthy froglet to die. They look all symmetrical and there are no weird discolorations.

Thanks for the help

Nik