So, before we get into this, I just need you all to know that I think Blue Dolphins, Malawi Dolphins, Blue Lumphead Cichlids or anything else you know Cyrtocara moorii as, is by far one of, if not my favourite cichlid that has come out of Lake Malawi- big call I know.
Without a word of a lie, these tropical fish are amazing. I have had a couple of groups in the past and I have never found them overly aggressive which is nice for a Malawi Cichlid, in fact they are as docile as Electric Yellows (Labidochromis caeruleus) which is great because as a combination in an aquarium they look stunning together.
Blue Dolphins are very easy to care for, but they do get some size to them, with mature males coming in at 10 inches so my recommendation would be at least a 5 foot aquarium for these fish. Being that they are open water Haplochromis you can keep the aquarium to a minimalist look with a few rock structures scattered about and lots of open swimming areas.
With a tinge of blue or purple through your lighting system, you can really make Malawi Dolphins shimmer within your fish tank. But to really make them pop, I suggest a dark background with a lighter colour substrate and the blueish colour through your light.
Being these cichlids are from Lake Malawi, they do better in hard alkaline water ranging from 7.5-8.8 pH. You can feed them a slightly more protein based diet as they are haps, however I feed them predominately New Life Spectrum Cichlid Formula as I feel that it is the best for food African Cichlids in overall.
In general these are stunning fish and if you have a Malawi Cichlid aquarium and you do not have at least one C.moorii within its walls I strongly suggest you look into getting one.