They are probably both fertile, I say probably because until you see them develope you just don't know, but they certainly are capable of fertalizing each others eggs. My L. grabhami (atlantic scarlet lady cleaners) breed almost every month, both shrimp carry eggs and they develope and hatch, though I have never seen the actual egg laying I'm guessing they hold their own eggs and the other one is the "father" then they reverse roles. I believe they carry their own eggs because I also keep several sp of Stenopus (coral banded type shrimp) which are one sex or the other (not hermaphrodites) and the female always carries the eggs, never the male. This means that she lays them, catches them on her abdomine and the male fertilizes them, if cleaners follow the same pattern, each one carries it's own eggs.