it is to attract other fish so that it can eat them.
is a species of angler fish.
An anglerfish
She doesn't make light for real her shiney and bright colors let you see that!
Some deep sea anglerfish of the aphotic zone emit light from their esca to attract prey. This bioluminescence is a result of symbiosis with bacteria. The bacteria enter the esca from the seawater through small vents. In the confines of the esca they can multiply until their density is such that their collective glow is very bright.
Anglerfish bones, anglerfish skin and a anglerfish personality.
it needs a very dark place to light it up and attract preys for it to eat...
What force balances the force of gravity on a hanging light?
Melanocetus johnsonii (anglerfish)
A hanging-drop is used to determine bacterial motility, besides brownian movement.
The purpose of hanging a thermometer outside is to determine outdoor temperature near one's home. Due to the erratic weather reports, people have chosen to determine their own temperature by hanging a thermometer outside.
anglerfish, I think.
There isn't really a name but fish like Angler Fish, Viperfish, etc. have light on its head