How do I catch the Red Gyarados easy in Pokemon Crystal?

weaken it put it to sleep and throw a ball

The difficulty in actually catching it varies. The pokemon is specifically vulnerable to electricity and so if you have the voltorb or machop (with an electric attack) at a level close to 30 this is the perfect pokemon to use. When throwing the balls it can vary like crazy how much it takes to catch it. After getting it to 1HP and putting it to sleep I used 6 great balls and 5 pokeballs to catch the damn thing but according to the person before me (whos answer was appauling) it took them 1 pokeball which I seriously doubt.

The red gadydos has the following attacks:

• Thrash (powerful fighting attack)
• Bite
• leer
• Dragon rage-watch out for that one.

I got i with one poke ball aswell.

I also caught it with one pokeball with about 30 health left