Hi.First go in seaside area 1 and defeat the three fishes in that area.Then you will have
the item that has a picture of piranha.Use it on the door that says"PLEASE GIVE ME A PROOF
THAT YOU HAVE CAPTURED ALL OF THE FISH IN THIS AREA FOR ME TO OPEN THIS DOOR."Then if you
show him the item he will let you in.If you want to go to seaside area 3 you need to
battle the door in seaside area 2 that says"YOU NEED STRENGTH TO GO TROUGH IN.ARE YOU
READY?

Yes No"
Choose yes and you will battle this viruses"

Battle 1: Mettaur, Piranha, Shooter
Battle 2: Puffy, Piranha, Shooter
Battle 3: Mettaur3x2, Puffy

Then your in seaside area 3.

To go in aquarium hp you need to go to that little house in the north east of the seaside
area 2.Talk to the orange navi and let fishing begin!!