Be careful with the crabs man! Being a Marylander (The biggest Crab eaters in America!) I can tell U for certain, that there are MANY problems that go along with Crab consumption!
1. Cholesterol: The Blue crab along with some shell fish contain higher levels of "bad" cholesterol then most other sea creatures. I am not certain that this will have a negative impact on Cichlids in the same way it does on Humans, but well it is out there!
2. Scavengers: The blue crab is a notorius scavanger that will eat horrendous garbage without so much as a millisecond hesitation. You hear fish keepers using the term "gut ... feeders" from feeding fish that are tp be used as feeders with high quality nutrition, so it can be passed onto the predator fish. This would put crabs at 180 degree other end of the spectrum in "gut stuffing"!
3. Dirty: Crabs lungs are considered poisionous to Humans. Most non Marylanders would not even consider "picking" the eadible meat from the shells to "eat" crabs. Even multitudes of Marylanders who love crab meat won't touch them with a ten foot poll and only do crab cakes etc...
4. Again as in my first point, there are along the lines of 1000+ times more Americans that have "allergic" reactions to crabs and shellfish, then there are who have allergic reactions to "finned fish". Again I do not know if the negative impact of allergies to humans are shared by fish at all.
5. Parasites: There is a huge challenge with parasites in shellfish and crabs that is easily greater then that of finned fish. If you have the "SMALLEST CHALLENGE" with feeding your fish live feeders due to possible parasites, then you would need to completely take leave of your senses to "NOT" worry about parasites from feeding them crabs.
And lastly, I don't know how you non-Marylanders eat your crabs, but in Maryland, we steam them in Beer and season them with Old Bay, Rock Salt and many other hot spices. The digestive systems of fish are not designed to take on "Spicy/ Hot" foods.