I was a mod and admin on a big Cyphotilapia site for years until it closed down-- I didn't own it-- and I can tell you far too many people have successfully kept fronts in 125s to say it can't or shouldn't be done. I've kept them myself for over 20 years and my last two or three breeding groups have been in a 135. In fact, some people who didn't see breeding in a larger colony in an 8 ft tank, split their groups into smaller (6ft) tanks and then theirs started breeding.
There are Cyhpotilapia stereotypes out there that are not true at all and some that are not always true. They're intelligent, curious, and more active than some think when they're comfortable. They're 'slow moving' except when they're not; in keeping with their size they're powerful fish, especially big males, and can move very fast when they want to. They can vary a lot by individual fish, so someone's experience with one or two groups doesn't always set rules you can count on. Getting a peaceful group or a successful breeding group in a 6 ft tank is not so much about tank size as getting a group that gets along, which sometimes takes some tinkering with numbers or individuals and sometimes with tank arrangement. Usually, it's the alpha male that sets the tone, but not always. I finally pared my current kapampa breeding group down to a trio when after some tinkering and a few different combinations it was still this one female that kept making trouble, fussing around, disrupting spawns, etc.. With her gone, this group settled right down and has been peaceful ever since, with the typical elevated energy and bit of fussing connected with a spawn.
