FWIW, even though my fish cannot SEE the moon and are not influenced by it's LIGHT, the mandarins still seem to be tuned into the lunar cycle. They spawn more frequently around full moons and the week following a full moon. A few more months of data will confirm if there's a definite correlation but going into this third full moon cycle, so far things seem to be shaping up like the last one.
FWIW,
MP