My take,
IMO and from experience depending on the species and the quality of the worms fed in MODERATION isn't bad . But, I personaly wouldn't suggest it be fed to most Africans.
Resson being most African Cichlids have lond digestive tracks. Meaning it takes them a long time to digest there food. Yes it was once believed that africans only ate greens and not live foods. Most all African Cichlids have a varied diet in the wild. Very few species depending mainly on one food source. So some do eat high protien foods but again have a variety in there diets.
Most foods fed to African Cichlids contain protiens . Blood worms are VERY high in protien and also are very prone to have bacteria. Now, this all depends on the quality of the worms. They MUST be rinsed VERY well and any viss. dead ones should be pulled out before feeding. Still even if you prep them properly and assure they are fresh there is still the chance that some fish don't exept it well. Causing the upset tummy leading to bloat.
The problem is not so much either or but a combanation. See Blood worms are normaly nasty from the get go. Most times there are more dead than fresh. Speaking of the type bought at your LFS which they keep in the fridge. There is also the freeze dried ones which IMO are not as bad. Add bad worms to fish are are prone to bloat and chances are the results may be ugly. Now this doesn't stand true for all Africans as I mentioned. I am speaking from experience in the past because I personaly feed both bloodworms and or white worms when avail. To alot of species that I keep which are mostly Lake Victorian some Malawi and some Tangs.
But i also feed them a variety of foods depending on the fish and it's natural food source. some get snails,worms,larva,daphnia,small mullusk,brine, baby brine,krill/ghost shrimp,assorted flake foods,bugs yeap bugs.
But over the years I have lost fish to bloat and not being due to a certain food in perticular. Some fish can and will bloat on flake food if they eat to much. So basicly as long as fed in MODERATION and fed aa treat and NOT as a staple diet the fish should be fine and also benefit from it.
Though I WILL remind that Blood Worms are VERY,VERY nasty and not the best source of live foods. This is just my opinion and from past experience.
My question would be,
What type fish are you planning on feeding the worms to ?
How many feedings a day are they now fed?
What other foods are you feeding ?
And a must fitration / water changes? ( worms are messy and can foul tank)
Alot of your Tanganyikan species do well with live foods including worms. (in moderation) While alot of your Malawi species tend to bloat up easier. Most my Victorians eat some source of live foods and also tolerate it better than the Malawi species do. Again not all fish nor hobbiest are alike though. A friend feed his fish pellets. Something I stoped doing years ago due to the amount of bloat cases I was having.
But just about everyone I know feeds there fish pellets with no problem so it just goes to show that it may work for one but not another.
Hope my 2 cents helps,
Danny