I've also previously seen seahorses for sale at a shop or two. Until now, I only knew of clownfish being raised for the aquarium trade. Places like the the Oceanic Institute also breed moi, mahimahi, shrimp, and some other foodfish for commercial farms to raise to maturity.
I'm divided over the sale of fish for aquariums whether farmed or taken wild. On one hand, it's great to introduce people to such animals and maybe get them interested and involved. On the other, there's the problems of overharvesting from the wild and what to do when the animals can no longer be kept. When I had aquariums, I would only use local fish so that releasing them back would be no problem. I used only handnets to catch them (except once with a bucket while out on a dinner date with my future wife but that's another story); no barrier nets, traps, drugs (illegal here), slurp guns (which don't work all that well anyway) and was very selective, taking only fish that I knew were compatible, hardy, and adaptable enough to thrive in an aquarium.
It sounds like OceanRider's marketing strategy strikes a good balance.