Kraken!

Since his encounter with the shark, Ezra had faced three other beasts, sending all of them to Quartez.

As he went on, he was even ambushed by a large school of glowing fish.

As per their name, these were fishes holding out a small glowing orb above their heads, thus illuminating the darkness with white lights speckled with blue dots. 

Females would be allured.

But if that was all there was, they would have long gone extinct.

The glowing lamps were there to lure in prey and obscure their sharp teeth from view along with the occasional flicker of lightning.

These things shot out lightning currents to paralyze their prey before tearing them apart, and as a school, the cumulative damage of lightning currents was tough to beat, making them predators in their own might.