Goby Question

[MikeYQM]

I'm thinking of putting a pair of Stonogobiops Nematodes, Hi Fin Gobies along with a pistol into my new 30 Gal tank. I've read they do well in a pair, as well as with a symbiotic shrimp; can anyone attest to this? Should I be getting a specifically mated pair, or will they pair up as clowns do? Is there a way to avoid a dual male pair?

Thanks,

Mike