i also am a breeder of many freshwater fish, i have a pair of black leopards one juvi and one sub adult thats showing signs of male. Dont go all wrasse police on me but I have them in a 20 long lol i wouldn't recommend them in a 20 but i cant say no cuz im doing it keep in mind both less then 2 inch and not much stock, fish wise because of competition. and water changes weekly and pods being added with water changes very pricy in all honesty to keep these fish in a small area. And be ready to upgrade they like to put on size pretty fast ive noticed but to answer the question
i believe all breeding in sw is based on moon cycle. not impossible but challenging. The most challenging part is the planktonic stage these animals go through. most fish dont rip apart food at this size (unlike so many captive bred shrimps do while in this stage). if you look at all the captive bred sw fish, they are fish that go through a very short plankton stage if one at all.
example clownfish, dotty backs and assessors from what i know just like cichlids surface spawner, young with yokes
Mandarins a bit challenging but a 1 month plankton stage. not raising young but getting to good enough condition to breed.
cardinals are mouthbrooders with quite large young.
wrasses ?? all reading says in nature on certain nights they will school together and pair off and do spawning runs that they will climb in the water column upwards to 36 inches (to sum that up polly wont happen or they will try but will stop once they break water surface) common problem in Mandarins too when breeding