This is Sakana, a gentle Merman, Siren or Fish Hybrid, completely depends on what universe you're looking at.

Sakana is a very curious creature and he wasn't properly taught how dangerous humans are but they tend to stay away nonetheless as humans scare all the fish away.

Sakana has grown up wild in the ocean, but she knows Japanese, English and a small bit of ASL due to an old lady named Kana who he met in the ocean. Kana took a small boat out to the ocean every day to come meet him and teach them fascinating new things. She was the one who named him, his name directly translates to 'fish' in Japanese. 

Although Sakana has been taught each language, she is best able to understand them and struggles a tad in actually conversing with the languages himself.

He knew Kana all throughout them growing up, but one day, when she was 17, she stopped showing up and he never saw her again. Unbeknownst to him, Kana sadly passed away in her sleep from old age.

Due to living away from humans all their life, Sakana has no concept of gender nor sexuality. His specific species is able to change their sex at will so he is happy with all pronouns, as they don't matter to him at all.