I bred them for years, in a set up that sounds like yours. If you are tall you will want the tank higher up than usual. They are surface oriented, and if you look down at a tank with a cover, you won't see them a lot. They cruise right under the surface, waiting for bugs to land and try to lay eggs. If your house is infested with mosquitoes, get some!
Mine ate crushed flake (no pellets - they are small fish), decapsulated artemia cysts and various freeze dried foods, as well as the live foods I use (but that most fishkeepers don't want). A good rotation of high quality protein flake brands (they did really well with bug bites flakes - closer to their natural diet) will do. I never use one brand, one type. Always at least 3.
I would try to get 6 to start, but the more the merrier.
I thought I had a dozen when a friend asked for some, and discovered I had more than 50. They are funny, because I rarely saw fry or juvies, but I knew they were there.They like magically appear as they've grown. It's like pigeons.
As Colin says, they jump. It's how they evade predators. They are slow runners, but acrobats. If there is an opening, they will find it.
I do put rocks to scape the tank, but the fish never go low in the water. They don't care.
Not too hot - 22-23. They'll live anywhere from 1.5 to 3 years unless you accelerate their cycle with heat.