Pokemon fire red catching mewtwo?

I'm playing pokemon fire red on my iphone device by gba4ios and so i need help catching mewtwo, and i'm not using my master ball for the legendary dog, so i'm using ultra balls, but can anyone tell me do i use freezing or sleeping? Because i thought freezing him will be the solution for my problem, so my question is that i used blizzard on mewtwo and he got frozen and then i used icy wind and now he isn't frozen and he killed my dewgong, what do i do? Explain alot please XD

Frozen and sleep status doesn't last that many turns. Your better option would probably be paralyzing since you'll halve his speed and keep him from attacking some turns. Paralyze also doesn't wear off and will last forever. So that with some ultra and timer balls would probably be better.

Yea I totally saved my master ball for suicune lol anyway there's only one way to catch mewtwo other people might say otherwise but, what worked for me was timer balls: get tons of them. Just lower his hp until he starts using swift a lot, that's when you know he's tired then start chugging the timer balls at him. It might take a lot but, he'll succumb after a flury of them.