I'm worried about switching out to Starmie on a starting Gyarados. If I start with Infernape and see Gyarados, I'll switch to Starmie which can eat waterfall but how well will it take an earthquake?
Breelom takes ice normal?HP: Electric Shedinja would win if Gyarados doesn't have stone edge and there isn't a sandstorm :P
Tangrowth is the best, IMO. Gyarados is forces to Ice Fang it for rather low damage, if he even has ice fang. Tangrowth has 100 Base HP and 125 Base Defense.
Also, Tangrowth can rock slide Gyarados.
Alternately, Breloom resists water, ground, and rock and takes ice normal, while it can rock slide or stone edge gyarados. It's defenses aren't as high, though.
The best gyarados counter is prediction. If you can switch in something that is hard hitting and still faster after gyra gets a DD, like Jolteon, you can make it switch out. Also, paralysis or burn really hurts it.
If you want something that will do something other than kill gyarados, Dusknior can use WoW and TPunch and have two more moves.
When it predicts a SwitchSince when does Gyarados DD on the first turn of a battle ?