Marine fish farm, huh? Sounds real interesting! There's a book called "The Complete Illustrated Breeder's Guide to Marine Aquariums" by Matthew Wittenrich that you might enjoy. It details a few species that are pretty easy to breed, however not on a highly commercial scale, in addition to how to setup breeding, food cultivation, etc. Here're a few popular fish in the USA that are supposed to be easy to breed in the aquarium; granted, they might not be fit to mass culture like most freshwater fish, but they spawn on a regular basis:
Banggai Cardinalfish (Pterapogon kaudernii), make sure to check for iridovirus if you use wild caught stock.
Clownfish (most species)
Dottybacks (Pseudochromis fridmani is commonly bred nowadays from what I understand)
Comets (Calloplesiops altivelis)
Assessors (Assessor flavissimus is supposed to be easy to breed)
Royal gramma (Gramma loreto)
From what I've seen on this forum, the majority of people here breed clownfish or banggai cardinalfish, since they're easy to spawn; there's not a lot of variety in terms of other fish species being bred on this subforum. Gogo7 is working on Stonogobiops nematodes, and Kizanne basically spawns whatever she can get her hands on (I think she's working on dragonets right now?).