its kinda like drinking alcohol. if you drink all the time everyday, you will get liver problems. drinking once in awhile wont do you any harm. i havent feed my SW blood worms ever. but my FW tanks i would feed them about 1-2 times a week. when i had an elephant nose fish thats all he would eat. well blood worms, and live black worms is all he would eat. i had him for about a year. then i learned the hard lesson about glass heaters.