if there is not too much size difference that one will eat the other. i have done it many times. make sure food is small enough to feed both and if one is vegatarian and the other is meat eater make sure you cover both nutritional needs. actually, it has been my experience and of others i have asked that combining species later in life is easier if they were raised together.
i am sure others can chime in on thier experiences.
i am running out of aquariums to place the fry. THere are already 2 aquarium with fry one has 10fry and the other has about 15. I have another female holding so i want her to release them into my 5 gallon.