Wow, I had a trio of these back in early 90’s also. Mine were slightly different variety than yours, East Asian, think yours are African/East Indian. They get up to 4”+. I swear these fish are smart and actually have a personality. After couple training sessions they would hop right in the palm of my hand to get food I had there for them.
If you’ve got 2 males and a female there can be some pretty vigorous sparing/display sessions, mine had spiked front dorsal, both dorsal blue with red on edge. When males displayed the whole side of fish would light up with blue glitters and then they’d pop up those 2 dorsal fins, absolutely stunning. You can also make a male display holding a mirror up to glass.
Prefer at least slightly brackish water, I just used arrowhead plant and some hydrocotyle as beach/water vine. If you’ve got 2 males when they get bigger and start sparring you can expect some broken plants. They’ll eat anything. When they got up to over 2” I started buying small crickets and gut loading them with old fish food, they grew like weeds after that. I think I had your tank I’d try some golden creeping Jenny as shoreline plant and some marimo balls in water. Both are known to be tolerant of brackish waters.
Get some breeding pairs/trio of sphenops/gold dust molly and when they have young and skippers stalk them you’ll amazed at how fast and accurate they are, they have big eyes and very keen vision. They’ll snatch a baby guppy or molly from water surface from across the tank in one precision leap. If it will fit in their mouth it’s food.
Totally amazing fish in every way.