Are blood worms ok for saltwater fish?

[George]

This may be a little off topic, but mysis shrimps that are being sold in the aquarium trade are not all the same species. Some brands mainly sell fresh water mysis (PE). Some are brackish/fresh water (hikari). Some are advertised as saltwater mysis.
FYI, if you want to train a fish to eat, instead of blood worms, you can try live black worms. The movements of live black worms attract some finicky eaters.