I have a batch of two week old Cynolebias (nematolebias) whitei fry. I have someone asking for pairs, and they want them yesterday. Any hints for sexing very young fry. Some are bigger, I assume those are males. None are showing color. All still have rounded anal fins. Any suggestions? Going to do a water change and hope for a quick growth spurt!

Aren't the females the individuals with the spots on the sides? I know other SA Annuals can be sexed in this fashion. Perhaps I can ask a friend who has some from this genus if his show the spotting.

Jeremy

Bob,
You have several options
1. wait a couple weeks
2. Send him a half dozen mixed size
3. Isolate a large and small for a week

Right now, the fish may not even know what they are

In my experience with whitei, the unpaired fins become slightly pigmented in the males while the females remain clear as the first sign of sexual dimorphism.

I spoke with my friend Tim and he confirmed that indeed the females show the lateral spot at an early age. Hope this helps!

Jeremy

Hi Bob, I had been keeping this fish for 6 years until recently, In my experience they have been very hard to sex before 4 weeks, I think you will find some males at 3 but the spotting on the females will start around 4. Lee's suggestion about a half dozen or so fry works good to. Hope this helps and i may have to get a couple pairs from you when they sex out

Eric Beyer