The tremendous structural and hydrological alteration of this prime habitat due to impoundment for mosquito control may have led to the extirpation of R. marmoratus from many of these areas. Maximum size is approximately 50 mm. It has also been observed moving amphibiously between ponds or burrows. The gonads of R. marmoratus are actually ovotestes that produce both eggs and sperm. DNA testing has shown that in spite of the fact that this species is clonal in nature, the genetic diversity within populations approaches that of sexually reproducing organisms, with the actual number of distinct clones being quite high.
Pure males are occasionally present in natural populations.
No males have been collected in the Indian River Lagoon. All the fish examined in this study were less than 150 days old. This study provided the first evidence that young adults of R. marmoratus sexually outcross. Since natural populations do not show this demographic, it was suggested that there may be an age-dependent shift in sex allocation from a female dominated population to a hermaphroditic population. This shift is somewhat similar to diandric protogynous hermaphroditism observed in other teleost fishes, particularly the Gobiidae.