Clamu is a purple sea oyster with periwinkle lips. She has a pink-red tongue. She also has some dark purple spots on its shell.
Clamu was a sea oyster at the Bikini Bottom Zoo who regularly spat a pearl 100 feet into the air.
In the episode "Tea at the Treedome", there is an oyster that greatly resembles Clamu tries to eat Sandy Cheeks.
In the episode "The Smoking Peanut", SpongeBob came to the Zoo and went to its exhibit. She was sleeping. SpongeBob threw a sea peanut at her, causing her to wake up and start wailing. She also threw one of its trainers, Joe, out of Oyster Stadium, where it was held. The crying could be heard all over the Earth, even above the surface of the water. SpongeBob feels guilty of making Clamu feel so bad until it was revealed that the person who caused its distress was Mr. Krabs, who had stolen its offspring, believing it to be free to take on Free Day. Fortunately, a zoopkeeper reclaims the offspring and gives it back to Clamu, and the citizens angrily throw peanuts at Krabs for stealing the baby clam, much to his dismay.
Clamu is emotional when her baby was stolen. Though, when unprovoked, she is calm and known to do tricks as mentioned in The Smoking Peanut.