This species has just been named as Lethrinops chilingali in a preprint paper from George Turner et al (subject to peer review) A new species of Lethrinops (Cichliformes: Cichlidae) from a Lake Malawi satellite lake, believed to be extinct in the wild
The zoo's label uses the name Lake Chilingali sandeater, although this paper says that wild specimens seem to feed more on invertebrates in mid-water than related species in Lake Malawi which find their prey in sandy areas.
This photo show the largest specimen on show, and all of them appear to be males. I presume there is a breeding harem off-show.
