A 30 long is a fair size for some Tanganykian shelldwellers on one end, and a pair of Julidiochromis transcriptus on the other. That size tank is too small for Malawi cichlids; simply not enough space to stock a sufficient number of mbuna, and too small for Hap's or peacocks.
If you want the colorful Malawi cichlids a 75 is a good starting point.
If you want the colorful Malawi cichlids a 75 is a good starting point.