deep sea fish looks are different to other fish
Answers
While it may seem like they live in the same environment (after all they’re in the waters of the same oceans), they don’t. The fish you see near the surface might as well be on a different planet from a fish living only a few kilometers below it.
The deep sea is lightless, cold, very nutrient poor (large tracts are essentially underwater deserts, albeit with a constant “rain” of dead things from the surface), and under extreme pressure that would literally crush a human into a pancake instantly. Try to lift a barrel of water. Heavy, isn’t it? Imagine thousands of those on top of you.
So any fish that survive there have to adapt to conditions that none of the surface fish will ever face. And this means rather spectacular adaptations, hence the “alien-ness.” Those which work best tend to be repeated across different groups. Things like bioluminescence (both for lures and counter-illumination), bulging or absent eyes, gelatinous bodies, back-facing long teeth, very slow metabolisms, etc. All of these are specific adaptations that enable them to survive in the depths.
In fact, almost all are so specialized to these conditions that if you bring them up to the surface, they will die. The lipids (fats) on their cells will literally melt when exposed to the pressure we are used to on the surface. Scientists had to develop special ways to bring them to the surface to study intact. This adds to the impression that they seem more alien than “regular” fish.
For example, one of the most famous photos of a deep sea fish is this guy:
It’s a result of that “melting”. It’s a tadpole sculpin. Although the previous image has given it the common name “blobfish.” In its natural habitat of depths from 2000 to 4000 ft, it really doesn’t look like a blob at all.
EXPLANATION:
The fishes which are found below the photic zone of the sea are called as deep sea fishes. The region below the photic zone doesn’t experience any sunlight and is highly different than the region above the photic zone.
Due to this variations the fishes existing in below as well as above photic zone has wide adaptation features which gives them difference in their appearance. Hence Deep sea fish looks are different to other fish.