Where do I find it in hgss, Im trying to level up my larvitar and dratini
take the red scale you got from capturing or knocking out the red gyaradous and go to mr. pokemon's house.
mr. pokemon was the person who you showed the egg too at the verrrrry beginning of the game, its were prof. elm sent you.
he will then offer to trade the red scale for an exp share.
since the red scale has no value, i'd advise it