As for frozen fish, I'm so paranoid about thiaminase I stick to trout or salmon fillets and just cut them into worm sized strips and freeze them skin on & all. Then I'll just defrost enough for the feeding and cut into bite sized pieces to avoid food battles, and sprinkle a little multivitamin with B1 on them. I had been using the gelatin suspensions but found that I didn't need to, mine all will eat the fish with vitamins sprinkled on so it saves me from having to make the stuff.

The problems I run into with silversides is the confusion on proper ID. There are fish they commonly call silversides which are actually smelt & also silversides that aren't smelt. Pond smelt are fine but other smelt aren't... So to be safe I've avoided them so far. One of the grocers here gets in nice big cheap bags of whole small silversides & smelt (with no species labeled) but without knowing exactly what species they are I don't want to risk it. There's too much overlap with the common names