Join Date: Feb 2003
Location: Boston, MA, USA
juilian75, first off, I don't have any experience in breeding these guys- or any other pencil fish, for that matter. Since you have problems in sexing your fish you want to try this approach, which seems to work extremely well for breeding a number of species.
Isolate your fish and condition them individually for up to two weeks. During this time you might start recognizing females since their bellies could swell up with roe (in mixed tanks they might actually spawn continously with all eggs getting eaten).
Pick male/female pairs if you can distinguish them, or just pick random pairs. Put them together in a breeder tank (best with a grid at the bottom to separate eggs from parents) and leave them for 1-3 days and check if spawning occurs. If not, move them back into isolation, condition them some more and try a different pair in the meantime.
If this info is too non-specific please disregard. Good luck... mario