Level 16
Marshtomp evolves to Swampert at Level 36.
Mudkip learns Hydro Pump at level 42. Sorry, he can't learn it if Mudkip evolves into Marshstomp or if it is a Swampert.
Mudkip evolves into a Marshtomp at level 16.
Mudkip learns Bide at level 15.
level 40
Level 32.
Level 30.
level 26 ^^
On level 20.
Level 16.
at level 32
At level 59