Which are bubblenest builders and are not free-spawners like Tetras and Cyprinids.
Still my all time favorites are Neon Tetras.
I raised a group of 50 or so a few years back from a spawning in a 5 gallon bucket I was using for holding fish and plants. The bucket they were kept in was half full of water Sprite and Java Fern, and I wouldn't have saved the babies if I hadn't first noticed the adults cavorting about in the roots of the Water Sprite. I put a little Betta bowl heater in the bucket to keep the temperature swings at night from getting too low, and put a black garbage bag over it for 6 days so they wouldn't get blasted by indirect sunlight.
Biggest non-intentional Tetra spawning I've ever experienced. Their babies are not the tender little marshmallows most books would have you believe. They took to immediately eating decapsulated Brine Shrimp and micro sized Golden Pearls, and grew like gangbusters in a 10 gallon grow out until I could get a 20 gallon set up for them.
I think neons are the first fish I remember seeing as a child, I may have been 2. It was in the kitchen of my grandparents' neighbours and had a bunch of neons in. I also remember the tiny little balls in the bottom of the thermometer....
I kept some while I was in primary school. I learned how to make them spawn by putting in building sand, which is usually just sand from the bergriver that is a humic river running from the mountain. They would often start spawning same day.