First you have to find Gilatic Grunt then you have to keep chasing him. Once you chased him then battled him, on the right is Cynthia then she should give you a potion to move the psyduck blocking your way.
you have to give them a secret potion that you get from Cynthia
Water pump ain't a move
After the explosion at the Great Marsh, follow the Cyrus and beat him. Then Cynthia will give you the SecretPotion, which makes the Psyduck's heads feel better and makes them move.
When you go to the lake by Pastoria city and you get its gym badge the champion will come to you when you go by it and give you a SpecialMedicine that you give to the Psyduck
you give them the potion that cynthia gives you.
you get the secret potion from Cynthia then go to route 10 press A in front of the psyduck then they move.
Psyduck can breed with psyduck, I think
Hypno, Alakazam, Mewtwo, Psyduck,Golduck, Slowpoke, Slowbro, Slowking, Medicham.
Psyduck was created in 1996.
beat all gym leaders up to that point then talk to him
Psyduck evolves at level 33.
in ruby & sapphire psyduck evolves at level 33