If you conduct competent quarantine with discus, achieve 100% of the result (yes, it is a long, hard work, but it is possible) then when feeding with a bloodworm, discus do not re-become infected. No need to panic around bloodworms.
Yes, problems with feeding bloodworms can be:
1. If the discus are infected with flagellates, worms, etc., then food, including the chitin shell of bloodworms, cannot be digested normally. Blockage, bloating, and death may occur.
2. When infected with cryptobia (this is also a type of flagellate), they penetrate into the intercellular space of the intestinal wall, form adhesions, tumors (I even have a separate article, but there’s an example of Flowerhorn), this impedes the normal functioning of the intestine, bloodworms do not digested, the fish may die.
3. A large bloodworm for a small disk (up to 7 cm) can be dangerous, but if you give a small and medium bloodworm, then there are practically no problems.
In general, I have long had the impression that bloodworms are a "scapegoat" for many aquarists. If there are digestive problems, bloodworms are to blame ... no, normal digestion is out of the question here ... but not bloodworms are to blame for this