The Catfish Club Band are a quartet of characters who appear only in The Little Mermaid: Ariel's Beginning. They are the house band of the Catfish Club, the underground music club in Atlantica that existed in opposition to King Triton's ban on music. Their band leader and vocalist is Sebastian, who also plays maracas. While these specific characters make their début in Ariel's Beginning, similar characters did appear in the "Under the Sea" sequence in the first movie.
They first appeared when Ariel followed Flounder to the club, where they sang "Jump in the Line (Shake Senora)" with Sebastian. At first they were afraid of her because they thought she would tell King Triton, but when she sings "I Remember" they come out of hiding and sing with her and welcome her into the club and give her the nickname "Red". The next night Ariel brought her sisters to come and Arista got to play Cheeks's saxophone. However, Marina spotted Sebastian and told King Triton, who locked them, Sebastian, and Flounder in the dungeon. Ariel freed them and started to run away and sang "Shake Shake Senora" again. Once they arrived at the shadowy place where Ariel found her mother's music box, they couldn't go back to Atlantica with Ariel, Flounder, and Sebastian because they didn't want to be sent back to jail. However, when they returned to save Flounder and Ariel from Marina's Electric Eels, they and Ariel were trapped by the eels. They were able to escape when Flounder tied the eels into a knot. King Triton arrived and took Ariel home, then they got a group hug. They arrived at King Trition's annoucement and bought back music and welcome Arista into the band and danced in the dancing train.
- Sebastian (Samuel E. Wright) is King Triton's chief of staff, royal court composer and the leader of the Catfish Club Band.
- Ray-Ray (Kevin Michael Richardson) is a sky-blue manta ray, who plays a bass. He is resident womaniser in the band. He has a deep voice.
- Cheeks (Kevin Michael Richardson) is a green blowfish, who plays a saxophone. He has a deep raspy voice.
- Ink Spot (Rob Paulsen) is a violet octopus, who plays a piano. He releases black ink when scared and he's the most cowardly member. He has the highest voice.
- Shelbow (Jim Cummings) is a teal sea turtle, who plays drums (including his own shell). He is the calmest member.
- Arista (Grey DeLisle) is King Triton's fifth daughter and presumably the only female member of the Catfish Club Band.
- Ink Spot is claustrophobic, and unlike normal octopuses (octopi), he does not display the ability to squeeze through small spaces or change his colour but he calms down when he squeezes a ball.