I feed frozen blood worms regularly to my rams and discus ..When they are not eating FDBW .
Kind of new to discus but been feeding the rams for years without issue .
I think besides the possibility of some bacteria or pathogen being introduced the blood worms aren't good is a fish keeping myth.
Clearly some fish should not be fed bloodworms regularly and in the same right some are just fine with them ..
What do I know though ?