From what ive seen and know cories like being in schools or some do anyways well theyll most likely injoy the company but that tank might be overstocked with the Clown loach for sure they get to big for that tank.
ok forget about the clown loach. In my 10 gl im going to have 5 cories.. I do enough filtration and cleaning of the tank weekly enough to keep em happy.
As long as you keep the water well-filtered and well-cleaned, you can probably get away with five Cories, but be ready to transplant one if you can't keep the pollutant levels down.