Cichlids, especially the smaller ones. Kribensis, Electric Yellows, brichardi etc. Don’t need a huge tank for a pair, and the offspring are worth something.

Small Plecos, like Bristlenose and Farlowella are relatively easy to breed and sell.

Dont overlook White Cloud Minnows. They can no longer be imported into NZ, so the only source is local breeders.

The trick is to find fish that are worth something, but can still be bred in a back shed fishroom. But because NZ has very strict (and expensive) import rules for fish there is a niche for home breeders that may not exist overseas where they have better access to bulk farmed fish from Asia.

Ian

If you hope to successfully raise the fry, you’ll need to keep (or move) the parents and the eggs in a 20+ aquarium. (Some people suggest moving only the eggs, but it has been my experience that the parents are far better caregivers than we are.) Please note that 20+ gallons is not sufficient for long term housing. 2 Angelfish will need at least 55 gallons long term. This is only for breeding purposes.
Be sure that the new tank is cycled, or clone your cycle from your current tank using filter media, plants, etc.
The breeding tank needs to be bare bottomed, (fry get stuck in gravel,) and equipped with a sponge filter. (Fry get sucked up by HOB type filters.)
The parents will guard the eggs until they hatch, fanning them to keep the water around the eggs fresh/oxygenated.
Once the fry are hatched, they will hang, (literally,) in a clump, subsiding off the food from their egg sacks. As the fry begin venturing away from the “blob”, the parents will often grab them in their mouths and return them from whence they came. Don’t worry, they’re not eating them.
Once free swimming, the fry will need to be fed fry-specific food several times per day. This food can be newly hatched brine shrimp, infusoria or commercial liquid fry food. The aquarium will need a partial water change once per day or several times per week, depending on the aquarium and fry size. While the fry are very small, the water changes should be done using a turkey baster or the like, with the water put into a bucket and examined for wee ones before it’s dumped.

That’s just the basics. If you’re wanting to raise these fish, I encourage a lot of research into the subject.

Good luck.