I always enjoy receiving reader questions, not only because I feel I'm able to help solve various wildlife-related mysteries for people but also because I sometimes get truly interesting queries, including a few that I don't know how to answer. Like this one:
"Dear Dr. Steen:
I hope you can tell us if a snake-bit fish is safe to eat, even tho' said fish has been disposed of. My husband had a nice bass on the stringer, still alive and in the water, when a Cottonmouth swam up and bit the fish on the head. Then the snake swam away. Hubby thought it might still be safe to eat the fish. He even went to the trouble of cleaning it, but I persuaded him to throw it away. In the off chance that this happens again, it would be good to know so I can avoid the argument all over again. Thank you so much.
Crittenden County, Arkansas"
What a good question. The best I could come up with was, "It's better safe than sorry." I could not say with certainty that the fish was safe to eat and I stressed that I would not want to risk it myself. But, I sympathized with the husband: I hate to waste food too, especially when I've gone to a lot of trouble to get it.
A Cottonmouth, Agkistrodon piscivorus, is a pit-viper. In general, pit-vipers tend to have hemotoxic venom, which means that the venom attacks red-blood cells (in reality, this type of venom causes tissue damage as well). This is in contrast with neurotoxic venom (possessed by snakes within the Elapidae family, including coral snakes); neurotoxic venom attacks the nervous system. Recent work has shown that many species of venomous snakes actually have a mix of both hemotoxic and neurotoxic venom but it is still safe to say that Cottonmouth venom is primarily of the hemotoxic variety.
When an animal is bitten by a venomous snake, most of the venom effects will be concentrated at the bite location. But, the circulatory system of a bitten animal will carry the venom throughout the body, causing blood clotting and organ damage. That's why I would be reluctant to eat a fish that had been bitten by a venomous snake: it's likely that there would be at least some venom throughout the animal, perhaps including the filets.
How hungry would you need to be to eat a fish that had been bitten by a Cottonmouth?