She is a recurring character in the series who was most notably seen in the episode "Bossy Boots " and "The Chaperone ." She is a sperm whale, which means Mr. Krabs was once married, and her mother was most likely a whale. She is revealed to be 16 in the episode "Whale of a Birthday ."
She seems to dislike Mr. Krabs when he is acting cheap towards her. She is almost the complete opposite of her father when concerning money. She has spent great amounts of Mr. Krabs' money in the past on superfluous things, and has admitted to maxing out his credit cards trying to buy shoes.
Despite her cheap father, she acts very bratty and spoiled often trying to control her father into getting her whatever she wants. She also cries whenever something goes wrong or she doesn't get what she wants. The irony is that usually children act like this when their parents spoil them which Krabs does the exact opposite of.
In "Selling Out ," Pearl can be seen as a baby in a scrapbook. Mr. Krabs was holding her in the picture: It's possible he could have possibly taken it. In another photo, she can be seen riding a bike with the guidance of Mr. Krabs.
In the past, Pearl seemed to like him so much due to The Chaperone, their relationship grew stronger, however in "The Slumber Party ," she showed a strong dislike for SpongeBob, it is unknown why, but Pearl seemed to be annoyed now by his actions. But in some episodes, they had a like/hate relationship, Some fans think this is love between SpongeBob and Pearl, but that's highly unlikely since Pearl is only 16. But her age is debatable due to multiple mentions of her birthday during the show.
Patrick ate one of Pearl's Krabby Patties in "Welcome to the Bikini Bottom Triangle ," but he doesn't like them as much as SpongeBob's. In the episode Tunnel of Glove. he tried to get SpongeBob and Pearl out of the Tunnel of Glove, which they were stuck
in. Pearl may know Patrick, or hardly at all.
Pearl and Sandy never interacted to each other officially but the only time seen so far was in Bubble Troubles when Pearl helped Sandy by giving air to her air helmet and said that mammals need to stick together. And at the start of the episode "Mr. Krabs Takes a Vacation " though it was just a brief cameo, Sandy was seen sitting directly in front of Pearl while Mr. Krabs was getting everyone (except Squidward) excited about the story of the vacation trip. Fans think they are rival love interests of SpongeBob. In "Texas ," she was one of the townspeople who wanted Sandy to stay in Bikini Bottom. She and the rest cheering for Sandy that she decides to stay in Bikini Bottom. They are most likely best friends.
Mr. Krabs is Pearl's father. Almost every episode Pearl appears in, Mr. Krabs is in too. Pearl loves her father very much but gets angry when he is cheap. Mr. Krabs loves Pearl very much too. It is possible that she is adopted or that Mr Krabs' wife was a whale.
Squidward and Pearl have an awkward relationship. In The Chaperone, Pearl refuses to go out with him to her prom. And in Welcome to the Bikini Bottom Triangle, he called her a 'drama queen', they were sunbathing while SpongeBob's Patty meter was empty. Pearl thinks that Squidward is such a "barnacle".
Friends in Bikini Bottom High
Pearl and her friends were best friends, in "The Chaperone," they didn't laugh at Pearl that SpongeBob is her prom date, then in Tunnel of Glove, they teased and humiliated Pearl that SpongeBob is her boyfriend, then they told the whole TV broadcast that Pearl and SpongeBob are dating. Then at "Drive Thru ," Pearl had new friends. It is possible she got new friends because her old friends made fun of her.
Although Pearl has been seen with her father many times throughout the series, Pearl has never been seen onscreen with her grandmother, Betsy Krabs.Source: spongebob.wikia.com