Chilumba Mbuna
Pseudotropheus tropheops,
These are 1 to 2 inch.
First picture is of adult male, second is of juvenile.
Location: Lake Malawi at Mphanga Rocks near Chilumba
Adult size: males: 5 inches (12 cm), Females: 4.5 inches (11 cm)
Diet: Algae (aufwuchs) grazer
Both males and females are yellow as juveniles and the males turn the stunning color shown below.