The most beautiful of the big Africans has to be the Chamsachromis Caerulius. It reaches about 12inches in length with trailing fins and the males have the most intense blue color.Ihave rarely seen them for sale over the six inch size,in my area they are brought in as 2inch silver fish for around 10bucks each which is not very atractive to those who may not know what they are.They are almost impossible to sex until around 4-6inches so it can be hard to pick out a male.I have a pair in my 180 with the female about six inches and the male is four inches but he already shows the fin and color difference.Their tankmates is a six inch eyebiter and my 18inch Emperor and three different types of Synodontis cats. The Champsachromis would be awesome in your 75 if you could find a male they do get aggressive when they get past the 6inch mark.Some of the trade names Ihave seen are Trout Cichlid,Malawi Torpedo.