I came to look at opinions on this. Seems more than 1 is ok, but concerned with QT. They will go into a 10gal QT. Was thinking of 2 or my 240gal. The ones in stock are maybe 1.5 inches. Too big already? Too small QT?
I have bred RG's. It's not easy to establish multiple individuals in the same tank. Not impossible, but surely not easy. Same sexes will often fight and it's virtually impossible to determine sex until they start breeding behavior. Like others have said, provide plenty of small holes, spread throughout the tank, for males to set up territories in. Be prepared to lose some. If you're one of the lucky few that have early success, great. Just don't be heart broken when/if some don't make it.