at the lake of rage outside of mahogany town
you don't get one.but you can in Pokemon gold,silver,heart gold,and soul silver.
magikarp will evolve at lvl 20 to a gyarados
you find a red gyrados at the rage lake
he is at the lake of rage after you encounter the red gyarados
Talk to Mr.Pokemon after you get a red scale from the red gyarados
bring it to mr Pokemon north of cherrygrove and you get a exp. share
You can use gyarados red,train it to level 50 use hyperbeam.
helll no
Gyarados do not evolve. Magikarp evolve into Gyarados at lvl. 20
you have to get a red gyarados and take the red scale and trade for exp share with mr Pokemon hope i helped!
After you fight the Red Gyarados at Lake Rage, go talk to Mr. Pokemon. He will offer you the EXP share for the Red Scale you get for beating/capturing the Red Gyarados.
well theres a very low percent that you can find one but in Pokemon heartgold/soul silver theres one in a lake