According to the signage, the yellow cichlid is an Elongated Lemon Cichlid (Neolamprologos longior). There were seven of them in the tank when I was there in June. And yes, the cichlid on the left is a Yellow-banded Cichlid (Tropheus duboisi) according to the signage and there were somewhere between 12 and 16 of them in the tank on my last visit (they're hard to count because they move in and out of the rocks).
@Summer Tanager
It's actually pleasant to see that a collection is making an effort at getting non hybrid cichlids as too often the Lake Malawi tanks are filled with various hybrids and weird colour morphs.
Sadly, the OKC Zoo's tanks aren't perfect either. In the tank featured in this photograph, the cichlids all appear to be pure species - there are Elongated Lemon Cichlids (Neolamprologos longior), Frontosa Cichlids (Cyphotilapia frontosa), Yellow-banded Cichlids (Tropheus duboisi) and some non-cichlid Leopard Ctenopoma (Ctenopoma acutirostre).
However, their Lake Malawi tank has a lot of hybrids and fish that I can't identify. The signage this summer listed the following species: Dogtooth Cichlid (Cynotilapia afra), East African Zebra Cichlid (Haplochromis obliquidens), Golden Mbuna (Melanochromis auratus), Kadango Cichlid (Copadichromis borleyi), Zebra Mbuna (Maylandia zebra), Red Empress Cichlid (Protomelas taeniolatus), Venustus Cichlid (Nimbochromis venustus), and Blue Mbuna (Lebeotropheus fuelleborni). I can pick out a few Golden Mbuna, a few Red Empress Cichlids, and maybe 3 Blue Mbuna, but the rest of the 40+ fish in the tank are a complete mystery to me and I think that most are hybrids. I'm hopeful that the zoo was scrambling to fill the tank before the exhibit opened and that maybe over time they'll replace the hybrids with pure individuals of a few species.
