Yes they were frozen / thawed lance fish , I think lance fish are the same as silver sides or at least very close in relation ..

I don't think they were already supplemented though , people use them for feeding to carnivorous fish so i don't think they would put supplements in.

That is what the shops around here sell for feeding to snakes like garters and yes it was a fish only diet , i was going to buy some earth worms the next time i was at the shop but that doesn't look like its going to happen

I know a lot of people say mice are the best but i grew up loving mice and such , so feeding small ones to a snake isn't what i want to be doing ...

I also just thought that it could be a vitamin D3 over consumption that caused a problem , The supplement has D3 in it as well at Vitamin A i believe and with me having a Uv bulb in there it could be too much D3 ?? But i don't know if that could have done anything at all ..

Oh and yes i don't live in the US , Im in the UK ..