With fish that have been line bred for color, lots of the traits you would need to determine sex are lost, and the deformities that come with inbreeding doesn’t help either. Venting is the most reliable way to tell for the ebjds.
Wow, great fish and wonderful photos! Ya, hard to sex EBJDs. Any spawns? I've noticed that if a pair forms, they'll both get dark, and the female will get really dark ... and then you'll also see the ovipositor.