If your talking about White clouded mountain minnows? I know a bit about them :) They like cooler water but can be kept in higher temps. They are a shoaling fish so 5 is minimum They can be a bit nippy but mainly leave bettas alone. They like a current in the water as there from fast streams. They breed quite easily if in the right conditions. Females are plumper and males and smaller and thinner.
5 gallon,natural planted tank with 1 betta.
20 gallon community tank.
6 gallon guppy fry tank.
Do you mean the feeder rosy red minnows? They tolerate 50-80 degrees farenheit. A ten gallon could hold one male and 3 females. They breed like cichilids, and are very cool fish. They just need caves, to lay eggs and stake out territory.
I only have 1 betta left, but he's a cool blue marble!