A few bowls will do and daily water changes while they are in quarantine are recommended. If they do get sick once they are in a sorority (sometimes one is all it takes) you have those bowls to fall back on.
Yes we do have a sorority. The thread you keep following is actually an account of our first attempts at making one. Needless to say it didn't go very well. *knock on wood* We seem to be doing a little better so far, but we're still having some bumps and bruises along the way.
Piece of advice number one: Quarantine is your friend when you get new fish. When we first got our new batch of females we had them quarantined about two weeks to watch for diseases (esp. columnaris b/c it tends to hit newly arrived bettas very hard and is extremely contagious) and it gives you time to get a feeling for their different personalities. You want to keep them in their own separate containers, not just separate from other species of fish.
Stay tuned for more advice...
PS-Starving_Poet is a good person to friend/ask too
Well, when I used to have guppies I read in the books that if they are in a sorority they do get bigger than being place with the males. I Don't really know how true that is. If your trying to get a specific color you should try putting the female and male with your desire color into its own seperate tank and see if they will breed true.
100 GALLONS WITH GUPPIES and tons of them and some zebradanios/glofish.20 gal. empty. And my furry friends,drews twin sis Lexy,and max my 17 year old cat.