The vast majority of recommended stocking on this forum that gets adopted are never documented because once the OP has stocked his/her tanks, the majority are never heard from again. No up dates. A few stick around, but often they end up changing their stock in short order. And there won't be any examples of 3 ft. tanks because these people are always get turned away with the advice on this forum, that it cannot possibly work, so they go some where else or avoid internet fish forums altogether. I've seen it work many, many times in 40 breeders over the years. Pretty common size tank for mbuna back in the '70's or 80's, IME.DJRansome said:If you don't see many success stories about Malawi mixes in a 36" tank in the last 15 years and you can't get anyone to recommend one in spite of a plethora of recent posts, that tells you something right there.
Here's one example of a recommendation from Sam Bonstein: http://www.borstein.info/profiles/victoria/paralabsauvag.html Rock kribensis in a 40 gal. and Malawi as the recommended tank mate.
I've utilized 3 ft. tanks in the past for cichlid communities/species tanks but wouldn't today only because I have enough larger tanks. I've got bigger tanks (180, 150, 125) and wouldn't utilize a 40 gal. for anything other then for a fry tank. But if i were starting out and had nothing larger, don't see why I wouldn't attempt to keep 4-5" mouth brooders in them. As far as the 3 "Victorian -types" I have kept (Astatotilapia latifasciata, A. bloyeti and A. burtoni), IME they are all compatible enough with mbuna, though i have not kept them long term together in smaller tanks (only briefly) so i cannot personally recommend specific mixes in a 40 gal.