I'm sure this question has been asked before, but I didn't see any old threads. I apologize ahead of time if I missed this somewhere. Anyways... I was wondering how to tell which grocery store bought fish was safe to feed to my guys. I've been feeding them frozen tilapia and just recently tried a bag of frozen "cold water shrimp." Both listed salt as an extra ingredient, and nothing else. I've been keeping large fish for almost a year now, so I'm still new to this. Any and all advice would be much appreciated. Thank you. 
