I would say 10 is too small in such a big tank, you could have 10 in a 20! I would say get at least 20 females and you could get another type of fish.
Sidenote: if you are buying all of them from a petstore I wouldn't recommend it. With buying so many females you are destined to get a few small males that haven't grown to size. I would find a breeder either on here or aquabid and ask for a discounted price for buying do many. It is a much safer route and if the breeder is on here you can ask them for another discount or just one for being on here. A lot of breeders have done it.