[Enigma]

BWA's advice is very solid.

Their spawning wasn't a fluke. The conditions in your system have contributed to it. As long as you don't radically change anything, they should keep spawning.

Take some time to get your cultures up and running, and then once you've got everything in order try to rear the fry. Go slow, and set your breeding system up a bit at a time as you have the funds/time/inclination.

Don't stress yourself out. Don't expect great results at first, either. It is a learning process, and you're going to make mistakes.