two adult firemouths, sitting on the bottom

Yesterday I bought an (alleged) sexed pair of adult Firemouths. The LFS who sold them to me said he got them from one of his customers. One is 4-5" including fins, and the other is about 2.5"-3". The LFS guy said he thought the smaller one was the male, but that would not have been my guess except for the fact that the bigger one is in perfect shape, with no wear while the smaller one is missing a good bit of its tail and pectorial fins. (I figured more chance a male would be beat up).

Anyway, overall I'd say the fish look well. No sign of disease, color is good. I let their bag sit for 40 minutes before releasing them into my 78 degree water. This was a little over 24 hours ago. I made caves and such for them to hide in (and they share the tank with nothing threatening: 2 small cories and 4 serpae tetras). Since then they've been mostly hiding, either together or (mostly) separate. The odd thing to my eyes (and these are my first new world cichlids since I was a kid) they are sitting on the bottom, just swaying their pec fins. When I fed this morning, they didn't eat and they ignored the mini cichlid pellets that were sinking wight in front of their faces. They are in a quiet area with little traffic to scare them.

Is all this normal adjustment behavior? The sitting on the bottom is scaring me a bit (fortunately, they sit on their undersides and not on their sides or anything). I just found the smaller one wedged behind a rock and the back glass.