yellow labs / Jack Dempsey

Question
I have a 30 gallon tank with 6 Jack Dempseys' all between half an inch to a inch long with one Texas cichlid that is 1 inch. and in my 55 gallon tank i have 2 yellow labs (yellow princes)(and a bunch of other cichlids but their not a problem) and it seems like no matter what i attempt to feed them they won't eat it, with exception for Black worms and i now know that yellow labs aren't supposed to eat black worms and I heard its not good to feed Dempseys black worms all the time (I've only feed them these worms once).
So Far i have attempted small cichlid pellets, freeze Dried Krill, Nutrafin Max (sinking pellets mainly used for bottom feeders and invertebrates), Color enhancing Cichlid pellets, Omega One first flake (a flake food that is suppose to address this problem in all freshwater fish), guppies, rosey reds, and frozen baby shrimp. Do you have any ideas what i can feed these stubborn fish.

Answer
First off what is the temperature of your aquariums?  If the temperature is to low it often will cause the fish to not eat or to be picky, its also possible they they are being over fed, this will also cause them to seem reluctant to feed.  Cichilds like temps in the 78F area and a several small feeding daily rather then one or two large ones will keep them interested in the food available.

Craig.