I've kept moorii with fronts and I won't ever do it again.
I bought 23 1-1/2 inch fronts from a breeder to add to a 125g that I had just set up. I also grabbed 5 blue dolphins because I liked how they looked - they LOVED the open swimming space and were really doing great. But since the fronts were so tiny I started to beef up their food intake so they would get bigger faster. I fed them frozen krill, pieces of worm, brine shrimp and extra New Life Spectrum pellets. They really started to pack on the mass, but a problem arose - the moorii were better eaters. They could out-swim the fronts and were soon eating the majority of the food - which led to bloat. Malawi bloat hit the moorii hard, and by the time I knew what was going on it had started hitting the fronts too. I had never thought that fronts were able to get bloat - I was wrong. The moorii that died would stick to the filter intake, and the fronts are piscivores and naturally eat fish flesh.. so the disease-infested carcasses became snacks (before I could remove them) and the bloat transferred to my baby frontosa.
They all had to be moved to a 29g hospital tank and treated with clout. When it was all said and done I had 8 F1 Mpimbwe frontosa left and a single, very skinny, very aggressive moorii. And that is why I won't mix mbuna with frontosa again - the differences in their diets can be disastrous.
Get some calvus or comps in there and you'll be happier. That, or feed your front/moorii tank nothing but NLS pellets.
Go with the comps/calvus or another predator and you can feed your tank earthworms or almost any frozen food you like. I have an 18" Fire eel in my frontosa tank and they get along great.