Haunted Aquarium

The Haunted Aquarium is among the many locations Luigi visits and is haunted by Shadow Kingfin and it's minions.

Main Complex
The main complex consists of all the exhibits and the control room, which is unlocked at the start. After obtaining the key in the control room, Luigi can go into the Penguin exhibit, which is haunted by Penguin Ghosts and other kinds of spooks.

Spirits:
Gold Ghosts

Garbage Can Ghosts

Janitor Ghosts

Penguin Exhibit
The Penguin exhibit is the first area in the aquarium unlocked by a key. It consists of the Swimming Area, the Feeding Area, and the Hatching Area. After obtaining the Key in the Penguin Exhibit, Luigi can go into the Dolphin Exhibit which is haunted by Dolphin Ghosts and different spirits.

Spirits:
Gold Ghosts

Animal Trainer Ghosts

Penguin Ghosts

Dolphin Exhibit
The Dolphin Exhibit is the next area unlocked and is haunted by all kinds of ghosts. Once Luigi obtains the key from this exhibit, he can visit the Shark Exhibit, where he fights the boss of the aquarium, Shadow Kingfin.

Spirits:
Gold Ghosts

Ceiling Surprises

Purple Bombers

Bowling Ghosts

Garbage Can Ghosts

Janitor Ghosts

Animal Trainer Ghosts

Dolphin Ghosts

Shark Exhibit
The Shark Exhibit is the final area unlocked in the Aquarium and is the boss area. After beating Shadow Kingfin, Luigi obtains the key that unlocks the fourth mansion and he also gets the Kingfin Rock which lets Luigi play the minigame Kingfin's Uprising.

Spirits:
Gold Ghosts

Speedy Spirits

Purple Puncher

Shark Ghost

Shadow Bonefins

Shadow Kingfin