Introduction:

Xanthism or xanthocromism is a phenotypic anomaly evidenced by the predominant production of xanthine, a pigment that gives the organism a yellowish coloration. In Costa Rica there are few records of organisms exhibiting such anomaly in natural environments.

Objective:

To present cases of xanthism in Costa Rican cichlid fish.

Methods:

We collected records of xanthism from social media, museum specimens and field work. In addition, we reproduced two xanthochromic specimens of Parachromis dovii to determine ontogenetic changes.

Results:

We recorded xanthism in eight species, six of them cichlids. In the case of the specimens raised in captivity, 100% of the offspring had xanthism after about four months. Conclusions: At least eight species of Costa Rican fish show xanthism, and a genetic (heritable) origin is presumed; this was corroborated in the captive breeding exercise.