Captain Barnacles >>>

The captain was resting in his cabin and calmly writing something down in his notebook. Then after a while, putting down his notebook, he took his accordion and putting it on his shoulders began to practice playing melodies again. He tried not to get distracted and to remember every single note

Captain Barnacles is the captain of the Octonauts and a brave polar bear. Along with being the captain, Barnacles is also the strongest member of the crew, and he's demonstrated that in a number of different episodes. He's also one of the most level-headed crew members, often dismissing Kwazii's outlandish stories about sea monsters and ghosts. His crew has a lot of respect for him. He's mainly one of the most iconic characters out of all the Octonauts, and plays as the main character mostly.
It's also been revealed that he rather fancies playing the accordion. Rather unfortunately, he has trouble playing it well, as shown in The Octonauts and the Orcas. So far, the only ones to appreciate the music have been a pod of Orcas. He is also an oceanographer and a map finder.
Captain Barnacles is also very fond of the Arctic Circle, as that is where he grew up with his twin sister Bianca.
In both the UK and US versions, Captain Barnacles speaks with a British accent.
As shown in the Manatees, it is revealed that he can rather be embarrassed by situations he gets into to. He mispronounces Shellington's name and gets his sentences mixed up when he looks at what's coming to him.
It is revealed in The Octonauts and The Caves of Sac Actun, that he has claustrophobia after being stuck inside an ice cave/hole as a cub. Being in the narrow Sac Actun Cave tunnels reminded him of how he came to fear tight, closed-in spaces as a young cub and throughout his adult life. It is interesting to note that at the time, Kwazii and Dashi knew about this, while Peso did not. This might be because Peso came to the crew later, or because Kwazii is considered more of a best friend or a right-hand man. However, Barnacles manages to overcome his fear with the help of Peso's bravery and support from Ryla and the other Octonauts.He is very kind, but takes his assignments seriously. He loves pancakes with vanilla very much.And he is also able to turn on the Octo-Alert if the animal is in danger.