It is not always easy to know your fish’s gender. In some fish species, the male is much larger than the female, but the opposite is also true. Some fish species have ZERO external gender characteristics, while others you can only determine by subtle behavioral cues.

Reproductive functions may also be limited or stunted in fish not receiving appropriate nutrition or space. When resources are scarce, fish will forgo reproductive function in order to survive. Fish in situations that are being stunted due to space or dietary restrictions are unlikely to reproduce and therefore, show any external signs of gender differentiation.

Fish will reach reproductive maturity at different ages and various species will have different maturity timelines. Provided they receive correct nutrition when they are very young and how much food they receive as juveniles will directly influence how quickly fish become mature enough to reproduce.