Adding A Few Calvus To My Frontosa Tank

[Lisa67]

I have a 125 gal tank which currenly houses seven frontosa and two calvus. Two of the fronts are about 2 years old, and the other 5 are one year. I would like to add more calvus, but am worried about them being eaten. If they are a decent size, the fronts wont bother them. Anyone know a good mail order company (or otherwise) that sells fish that aren't tiny? Thanks in advance!