salt baked red snapper - what a mess!
Don't know how you set it up but, if you did it this way:
Salt layer (Kosher salt - don't use table salt) on bottom of roasting pan
Layer of some variety of fresh herb (your choice but Id suggest bay leaves) covering the salt layer.
Fish laid on top of those layers with whatever herb or spices you want to use placed inside the fish cavity.
Salt mounded over top of the fish, leaving both ends (hed and tail) uncovered
No need to use the egg or egg/water glue unless you want to. I think that the egg/water mixture makes the crust difficult to remove.
I like to use a skewer or some similar item to seal the fish cavity opening as much as possible so that the moisture from the fish doesn't combine too much with the salt because when the salt disolves into solution with the liquids it can tend to infiltrate the fish.
Also got to make sure you don't overcook the fish with this procedure