No, Shroomish cannot learn Mach Punch.
It doesn't learn Mach Punch.
If you didn't choose Torchic as a starter, raise a Shroomish to Lv 23, evolve to Breloom, let it learn Mach Punch and/or Counter. You'll defeat your Dad in no time.
At level 22 into Breloom, he learns mach punch too, great for the gym battle against your father, Norman.
It can learn Mach Punch, but it should be able to learn upon evolution. Breloom is able to learn Mach Punch at level 23. If you think it was forgotten, it can be relearned by the Move Reminder in Fallarbor Town. If you are playing Pokemon FireRed or LeafGreen, the Move Reminder can be found in Two Island in the house next to the Game Corner.
Then he doesn't learn it anymore.
Mach Punch
Shroomish can learn flash.
mach punch hyper beam thunder roar of time
Shroomish doesn't learn Sleep Powder.
Shroomish doesn't learn Sleep Powder.
Shroomish's stats are really subpar, even when it evolves (at level 24). If you're fanatical enough to keep it unevolved until it's in its fifties, it'll learn Spore, which sleeps EVERY FOE IN THE ROOM. Then, feel free to evolve it into Breloom to capitalize on its powerful, high-range Mach Punch. The stats are a pity, though.
It's evolution, Breloom, can learn Spore and Focus Punch. Leech Seed is pretty nice as well. What LSD is to common folk?