Okay, now I am carefully looking out for red eyed carp.  Do you have one?  
 
The purpose of this study was to investigate the inheritance of red eyes in ornamental koi, a variant of Common Carp Cyprinus carpio. The study included crossing fish with different eye color phenotypes and analyzing fish segregations in progenies.
 
Gomelsky et al. 2016 NAJA 78 251-258.pdf (ksuaquaculture.org)