Manolo is the unseen crustacean cousin of Pepe the King Prawn.
Pepe mentions Manolo in It's a Very Merry Muppet Christmas Movie at the sight of Rachel Bitterman's small toe (saying "this little fishie looks like my cousin Manolo").
Pepe also referenced Manolo in the blooper reel for his 2002 Long John Silver's commercials (turning to one of the cooked shrimp after a take and saying "Manolo, go change.")
Manolo is mentioned in Pepe's 2008 book It's Hard Out Here for a Shrimp. When listing "wise investments vs. not so much," Pepe puts Manolo in the "not so much" category.
Pepe mentioned Manolo yet again in the Muppets' January 2010 appearance on America's Funniest Home Videos when a video was shown of a woman eating a prawn. Pepe claims he recognizes one of the crustaceans in the video and feared that it might be his cousin Manolo being consumed. Kermit reassured Pepe that they likely used a "stunt prawn." This was good news to Pepe who remarked: "I hope so, Manolo owes me money." (YouTube)
In a 2014 commercial for the Epcot International Food & Wine Festival, Pepe tells the Swedish Chef that his cousin Manolo once made a great shrimp taco, and, come to think of it, he's never seen Manolo again. An on-screen disclaimer at the end of the video read: "No shrimp were harmed in the making of this video (except Pepe's cousin Manolo)."
Pepe mentioned Manolo in a series of 2015 New Year's Eve tweets, revealing that "Ryan Seacoast" had hosted his cousin Manolo's clam bake and asking Rizzo if he could bring Manolo with him to Dick Clark's New Year's Rockin' Eve. (Tweet 1 | Tweet 2)