4th Gen Yeah I'm fishing for something...

[Disturbo]

So around march I decided it was a good idea to buy one of those distribution cartridges.
I wondered if it actually work about a day ago and in the way of unlocking mystery gift in my for-some-reason unstarted pokemon pearl (gotta love gen 4) I've decided that I want to capture a very specific pokemon before battling the rival. A very oddly specific pokemon, and a very stupid one. Using the old rod, I'm aiming to capture a level 15 magikarp. Funny thing is, the level range in all the fishing spot is... well, it is 3-15. Man I want tackle on that thing...

 

[Enpatsu Shakugan]

Just capture something you can battle with to catch any level karp, use it to slowly grind up karp until it learns Tackle, release other Pokemon= you're ready to go.

Believe me, trying to do it any other way will be a drain on your life for no real reason.