I have named him Kandō-ko which means disowned child. but before he feared the water he was Umiko "child of the sea"
Edit:

History snip: As a pup something happened as he was hurt by water, or in the water and ever since he has been terrified of it, so he ended up on Japans shore and loved the customs there and decided to live there for good. In honor of his heritage, he got the koi pond tattoo, because he likes ponds, but not the ocean. So its his way of honoring the ocean. OTL gomen.... truly sorry if thaat makes no sense