I try to stick to things that I know are good and are as safe as possible. Right now everyone gets f/t rodents (if they'll eat them) and f/t silversides, though I'm starting up a tank for feeder guppies this week because of the hassle of dealing with silversides. I'm getting the guppies from a reputable breeder to minimize the risk of parasites. I know it's not as cost-effective as silversides, but the reduced time and effort of cutting and thawing smelly silversides is more than worth it to me.