I am soon getting a new, big tank

I hope to gather most of my fish in it, among those 5 julii corys.
The water will be about 50 cm/ 20" deep (after gravel is added). Is this depth OK for the corys?
What should the maximum depth be in a tank with corys?
(I once read that the water must not be too deep for corys, but don't remember where)