Variety is definately good for our slithery friends .... and I'll keep up putting vitamin drops in the water ... sometimes there is just too much conflicting info .... mind you .... even so-called experts can get it wrong e.g. W.P. Mara (author of 'Garter and Ribbon Snakes') is guilty of generalising and even lists goldfish as a perfect food item!!!
Quote - "Goldfish are offered to captive garter and Ribbon snakes probably more often than any other food item. Goldfish are inexpensive, provide good nutrition, and can be obtained in most any foodshop."
Thiaminase isn't even associated to anything in the food section .... it is only mentioned very briefly in the book at all and then .... it is only refered to as a vitamin deficiency.