Quote Originally Posted by Snakey Lakey View Post
The Bluegill has been in the freezer so long that it is rather freezer-burned, almost like freeze-dried.
It shouldn't be unsafe in any immediate sense, but sub-optimal freezing does degrade the nutritional content of the fish. Vitamin E is the thing that you'd be most worried about there. It would be easy to just puncture a vitamin E capsule and drip some on the food before you feed it, but I've got no idea what an adequate/safe supplement level is. There's also a general vitamin powder available that you could dust the food with, that might do the trick.

Sometimes I feed a few (not many, and not often) bites of Tuna that cling to the can when we make Tuna-salad, is that ok?
Canned tuna is processed with a lot of salt, which the snake wouldn't normally get. I honestly don't know if it has the right kind of thirst response to deal with that safely. Unless you think the snake *really* likes it as a treat, it would be better to avoid altogether.

Three times I have fed about a half-dozen bites of canned cat food cut in half
Your call. There's a well-known garter hobbyist/expert that advocates feeding cat food as a staple diet. Pretty much everyone else thinks it's a terrible idea: http://www.thamnophis.com/forum/husb...tml#post110759

In the past this snake has also eaten bits of beef, beef-heart, chicken, frozen-thawed jack-rabbit, and partially canibalized mouse fuzzies.
Those are probably all fine as part of a varied diet. I think the consensus is that garters are pretty opportunistic in the wild. BUT you should remember that any meat (strips of meat, without the bones and guts of whole prey) is going to be very deficient in calcium, including fish. So if most of your meals are bluegill fillet or strips of butchered meat, you should dip the items in calcium powder every couple of meals.

I saw on the list that Anchovies contain thiaminease; but what about the canned variety from the grocery store?
It's true that the canning process would inactivate thiaminase in anchovies and sardines, but again the salt (and oil) is not going to be good for the snake. Make some pizza, or throw 'em out - sorry!