Gender recognition in Metynnis silver dollars is relatively easy - Males typically have a bilobed anal fin, whereas females' anal fin does not have a second lobe about halfway the total length of the fin. In addition, the entire anal fin of FEMALES is much more colorful (Red) than in males (mostly white, with a bit of red). Of course, during courtship, other colors (mainly black) become evident temporarily. In adult fish this is easily observed.
What is not easy, is the early detection of gender in small juvenile fish. As with other fish, young ones all look alike. Only after certain age/size, differences begin to be noticeable, even if one knows what to look for.
Back in November I bought 4 very small tiger SDs, Metynnis fasciatus. Too young for even a hint at genders. They ranged from about 1.5-2 inches.
Now they range 2-2.5", and since about the beginning of January I have been able to observed clear differences leading to conclude that I have definitely two males (the two largest), a certain female, and one who could end being either. I hope I don't end with 3 males and one female (female would be harassed), but even if I do, it is all cool.
Photos below, --> 1) The setting. 2) Adults male and female (not my fish, just Googled them). 3) shots of the growing young ones, now showing incipient differentiation.
The setting -
Adults, male, female -
My young ones, male, female -
Got any young Metynnis (or other SD genera) you want to share here?
Cheers!
What is not easy, is the early detection of gender in small juvenile fish. As with other fish, young ones all look alike. Only after certain age/size, differences begin to be noticeable, even if one knows what to look for.
Back in November I bought 4 very small tiger SDs, Metynnis fasciatus. Too young for even a hint at genders. They ranged from about 1.5-2 inches.
Now they range 2-2.5", and since about the beginning of January I have been able to observed clear differences leading to conclude that I have definitely two males (the two largest), a certain female, and one who could end being either. I hope I don't end with 3 males and one female (female would be harassed), but even if I do, it is all cool.
Photos below, --> 1) The setting. 2) Adults male and female (not my fish, just Googled them). 3) shots of the growing young ones, now showing incipient differentiation.
The setting -
Adults, male, female -
My young ones, male, female -
Got any young Metynnis (or other SD genera) you want to share here?
Cheers!
