Welcome to TONMO, the premier cephalopod interest community. Founded in 2000, we have built a large community of experts, hobbyists and enthusiasts, some of whom come together when we host our biennial conference. To join in on the fun, sign up - it's free! You can also become a Supporter for just $50/year to remove all ads and enjoy other perks, like Site Search. Follow us on Twitter or Facebook for more cephy goodness.
most cuttle keepers see distinctive displays and characteristic behaviors when they're sexually mature, and find them very hard to sex before then. I don't know of anyone who's observed Metasepia enough to have seen if that works, though... if marinebio_guy got his metasepia studies underway, perhaps he'll chime in...?