umm...well
the thing with trets is they are a) an awesome fish (my favorite african) and b) vicious. You can't keep more than 1 male in a tank, or the weaker one(s) will be eliminated (killed.) One male will usually do alright with other fish, but once you throw a female in there, they form an evil supervillain team and eliminate (kill) every other fish in the tank.
the other thing with trets is they get about 6" full grown. A 10 gallon isn't sufficient. I would say 55 gallons bare minimum, but would really recommend the larger front to back dimensions of a 75 gallon (i am waiting to get my tret for this very reason, even though I had a 55 gallon available)
another thing is that they require a hard water with a high pH (above 8).
I would recommend taking them back, or if you're stuck on trets (can't blame you
) , take the weak one back and get a big tank for the strong one.
If the LFS told you 10 gallons would be ok for 2 very aggressive african cichlids that grow to 6", I would seriously not give them any more of my business, they're dorks.
If you want a good african cichlid to keep in a 10 gallon, try shelldwellers or julidochromis, but even still, get your info before you go to the LFS, lest you be persuaded by them to host a colony of frontosa in your 10 gallon.
=)