Dropping mackerel slices into a gathering place of golden-shining fish resulted in... [Hole Fishing]

This is a video about hole fishing. Surprisingly, you can catch various fish species such as Black Rockfish, Scorpion Fish, Grouper Fish, and Tidepool Gunnel in this fishing method, making it highly recommended for beginners.
Despite looking golden, it's called 'Red Seabream.' What exactly is the connection with the color red?
Tools used:
Daiso's fishing rod
Daiso's bucket
Radio pliers
A trap called "brakuri" used for hole fishing
Filming equipment:
GoPro 9 Black