Suggestions by @laylachat

Tidal Whale

as Whale in Aquarium

Thumpback

as Whale in Aquarium

Thumpling

as Whale in Aquarium

Ms Whale (Skylanders)

as Whale in Aquarium

Don the Whale

as Whale in Aquarium

Ganvhale

as Whale in Aquarium

Whamon

as Whale in Aquarium

Monstro

as Whale in Aquarium

Wailmer

as Whale in Aquarium

Wailord

as Whale in Aquarium

Winona the Whale

as Whale in Aquarium

Pearl Krabs

as Whale in Aquarium

Willie the Whale

as Whale in Aquarium

Stephanie the Starfish Fairy

as Starfish in Aquarium

Seastar Fangire

as Starfish in Aquarium

Sploshy the Starfish

as Starfish in Aquarium

Herb Star (SpongeBob Squarepants)

as Starfish in Aquarium

Bunny Star (The Patrick Star Show)

as Starfish in Aquarium

Cecil Star (The Patrick Star Show)

as Starfish in Aquarium

Patrick Star

as Starfish in Aquarium