I may have misunderstood your post, but I wouldn't advise mixing species such as reidi and kelloggi in your tank. One of the greatest sources of risk for disease and mortality I've observed (IME) is putting "symptomless carriers" with long term captives... There was some real data collected by a pathologist on a seahorse site that supports the idea that some species tend to carry infection that does not kill them, and which quickly kills non-resistant or non-tolerant species.
BTW, years ago, I bought some "black seahorses" from the Marine Center (no longer in business, I think). Of the three I bought, which came as young adults, two survived about five years. I don't know what these were for sure, but I am pretty sure they were among the first net pen raised seahorses in the trade. They kind of looked like dark colored reidi, but maybe were kuda (which can be a catchall, anyway).
Domestic captive bred (raised in a tank from fry) and bought from the breeder is best. In general, net pen raised (in the ocean) is better than wild caught. Treat net pen raised like wild species, with proper QT, possible prophylactic meds (i.e. for intestinal parasites). Domestic captive bred seahorses are likely to be healthy, acclimated to aquarium conditions, not highly starved/stressed, recognize frozen food. Can't expect the same with WC or net pen raised. The import process also adds a lot of stress, many wholesalers have no idea how to handle seahorses.