As Louis mentioned earlier, that is indeed the easy part for most any fish. Getting pairs is easy, setting up an environment to induce spawning is often as simple as looking at their natural breeding environmental conditions and replicating those in the lab. Oh, and of course heavy and nutritious feedings for the brood stock. Getting animals to breed is basically all about making them well fed and happy, than nature takes it course
The trick to larval feeding is indeed the first foods. The easy fish to raise will take rots or artemia nauplii. However, most seem to need something else. Some fish larvae for instance specifically eat things like clam veligers or barnacle nauplii, etc. If you have ready access to natural seawater, than plankton tows to collect wild plankton can be very helpful in the case of fish that won't find rots acceptable as a first food.
