Blue Goatfish (Parupeneus cyclostomus) マルクチヒメジ also Goldsaddle Goatfish and Moana Kali
The Blue Goatfish can get up to 50 cm. It is usually blue or blue and green with a yellow saddle behind the dorsal fin. Sometimes they can be reddish. They can also be all yellow. Amami 2023
Here is a yellow “Blue Goatfish” with bleached coral. The yellow ones are not very common. Amami 2024
Here is another color variation of a Blue Goatfish. The yellow ones stay yellow, but the others can change colors. Amami 2024