There are many parts of their appearance that is different in each species of Horned frog. Cranwellies tend to be duller and color and usually are Olive greens/browns/tans/rusty browns. Where as Ornates are brighter Greens/yellowgreens/browns/reds. Also Ornates have false eye spots on the back of their eyelids. Different facial features and body shape as well. Ornates tend to get a bit larger too.

No worries about not being able to find him. They are nocturnal and burrow during the day to sleep. He's in there somwhere. Under the edge of that huge rock/near the UTH/ or near the fake plant would be good guesses as to where he would hide.