They shoudn't. I guess if you had the Jaws of the cory world he might attack anything. But I had a school of corries along with two ADFs and an uncontrollable guppy population in a 20 gallon for about two years before I decided to do some re-arranging. You shouldn't have any problems mixing the two.
Mt 20 gallon right now has 5 albino corys and 2 (now 1) ADF. I figured he must have gotten out, but the tank is almost completely covered. There are also no froggy parts anywhere in the tank.
Hmm, have you done a water change recently? He could have gotten swept out. Other wise I'd guess he just died, and the corys ate him after that.. My neon died one night, and the corys munched on him, til all was left was a little skeleton..
I did a water change last night, but it was after he was already missing. During the water change I looked in every nook he could be in with no luck. ???
Did you check inside your filter? I had a paddletail newt go missing for a week, until I did a water change and cleaned out my filters cartridge, the newt climbed in there and got stuck underneath.
Not in the filter either, he must have escaped. I searched the entire apartment for him and found nothing. I wonder why he ran away, the water quality is perfect and he gets fed daily with no competition.