Usually hippocampus erectus or reidi. Have several 20g's for separate growth stages and for fry-juvy you can divide a 20g (circular water flow always seems to work best for fry-juvy). you'll also need 24-72 hr nauplii stages for feeding progressions ....just a very quick rundown.
I would have the primary breeding adults in your main display tank and at least two 20g tanks for offspring. The initial fry will be rather pelagic and need circular water flow for optimal results, but will eventual hook in the coming days-weeks (just depends). The fry will also probably need a Formalin treatment (you'll see them shake their bodies and flick their tail as if they itch). The fry stage should be on its own filtration, but juveniles can be hooked up to a separate sump if you wanted to expand (in other words juveniles occupying two 20g hooked up to a 40g sump). Just depends on how extensive you want to get. The naupllii would need to be hatched out and separated into containers 24hr(old), 48hr (old), ans 72hr (old). This is just easiest ime. The growout tanks can have plastics for hitching.