in the 8th gym city
About 30 I would say
stock up in ultra balls or in apart of the game you would have found a master ball if you have all ready used it or you have not found it use ultra balls
You should take 20-30 dusk balls and 20 ultra balls. You are not guaranteed to catch it. It is better to put it to sleep. I would use a master ball if I were you. Hope I helped you.
I would get a Pokemon with the move false swipe (e.g. Gallade,Sceptile etc) and also carry a lot of Ultra balls with you to increase your chances of catching Pokemon.
i usually find it while I'm looking for other Pokemon but you can catch it by flying to a place he is not near and he may go there. (not a guarantee) oh and take lots of money from your mom and buy balls. best balls would be: quick balls, heavy balls, ultra balls. do NOT use timer balls, poke balls. (you have practically no chance) AND DONT USE A MASTER BALL! save it for ho-oh or lugia. hope i helped
You should also then put the Wild Pokemon Modifier code on. This will allow you to change what you encounter in the wild. You can change the pokemon that appears by throwing away the correct amount of Master Balls that will automatically appear in your bag and here's how it works: The number of Master Balls you obtain will be 386 and that is the total number of pokemon all together from Kanto, Johto, and Hoenn. Since you want a Squirtle to appear, you would throw away 379 Master Balls. You also get 100 Ultra Balls and this represents the level the pokemon will appear at. If for say you want it to appear at level 5 you would throw away 95 Ultra Balls.
luck but i suppose that's not the answer your looking for so i would say bring ultra balls and a Pokemon that can put it to sleep right away.
I would recommened the ultra ball or master ball [if you haven't used it already which most people have]
Moltres is at the peak of MT. Ember. I would bring a ton of Ultra balls (like 45), and a Pokemon that knows sleep powder or yawn.
Mantine are quite uncommon but appear on the sea-route between the Whirl Islands and Cianwood. I would take a few ultra balls and dive balls, as these dont like to be caught
If you are good at catching legendaries, then you would need at least 10 but 15 would be safe. If you are not good at catching legendaries, then I would get 25 ultra balls.
I would Recommend Ultra balls.