I have been feeding tilapia filets to my garters for a bit, along with worms and rodents. the snakes that are eating just the tilapia are showing some odd signs....bodies twisting, kinda like the red siders I had a few years ago that wouldn't take rodents....I was feeding catfish filets as they were cheap...found out the contain thiaminase....lost the poor snakes too. some of these are doing a little of the twisting now...not as much as the red sideds did. I can't find tilapia on the list of thiaminase/non-thiaminase list.....I am wondering if they do have a small amount in them.... I am not taking any chances now....as soon as the little bit of it left is gone..I am switching to salmon, trout, and cod....are on the good list! anyone else have this problem????