Once upon a time I was part of the (silly) Anti-rodent campaign...

Not any more.

If you buy frozen rodents from a reputable place like rodent pro, You are assured a CLEAN (chemical / parasite free) food that provides both nutrition and high moisture content.

Support your lizard correctly and it will not get fat on mice.

In regards to those crayfish, I wouldn't worry too much if the water is clean, chances are it has to be cleaner than some of those swill holes in third world countries.
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Regards,
Wayne A. Harvey
Thamnophis US
Savannah Monitors
Snakes and Lizards, It don't get any better....