The North American freshwater fish family Centrarchidae is well known for
extensive natural hybridization, but there are no reports of voluntary spawning between
genera. We document courtship and spawning in an aquarium between two separate pairs of
a male Rock Bass (Ambloplites rupestris) and a female Sacramento Perch (Archoplites
interruptus). One trial resulted in a low frequency of fertilized eggs, but these did not survive
beyond the blastula stage. Fossil and molecular evidence suggests that these species have been
isolated for at least 15 million years, so this spawning implies that courtship among species
can persist longer during species divergence than previously appreciated.