Bioluminiscent tricky thing in da sea.

It would be pretty large, and have luminescent markings on it resembling those of local fishes.
A large shark or something similar would approach to try to catch the fish, but then get eaten by the large creature.
It would be covered with irregular patches of glowing bacteria, with silvery scales around to help generate the appearance of a school of fish.
Incidentally, each fish has its own unique pattern, similar to cheetah.
It would have several sets of eyes, as it never knows when it will come under attack, and therefore, must defend.
Occasionally if a predator approaches, it will try to run away, as it knows it cannot eat another creature with a full stomach. If it does not succeed, it will then maul the creature.
It usually travels close to a predator, baiting it to attack.

is it related to spotty?

Pardon?