Over the past several years there have been numerous reports of regurgitation and possibly death from feeding silversides. from what been able to surmise, I attribute the issues being related to them being too boney as well as the quality. I don't believe quality control is very strict when it comes to silversides considering they are marketed as a bait fish. I also don't believe I've ever seen a package labeled for human consumption.
I don't have any scientific data, but it has been a pretty consistent trend when it comes to anemones.