I got my imbellis from wetspot on aquabid, they're located in washington. They sell them as unsexed, but I received 7 out of 7 as females. The customers at the actual shop usually pick out all the males very early on when they receive them, so if you order online you usually get all females even though they say "unsexed".
I do not recommend ordering from them as it will be a "blind" buy essentially, and if you plan to breed, you'll want good quality stock to start with.
If they are true wild caught, you will hardly ever see them in your tank, they'll always be in hiding. I managed to cross breed one with a black dragon ctpk. I've tried 4 times to breed these hybrids, but the fry have never made it past the 2nd week, they just never get to the free swimming stage and just bob up and down for weeks until they die, however, recently (1 week ago) I've managed to get a spawn recently with about 4 out of 20-ish of the fry are now free swimming and might make it to adult hood.