The Whalefish: The Deep Dark-Dwelling Fish

selim12 January 2, 2024 0 Comments

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Meet the whalefish, from the family Cetomimidae. Found only at remote depths starting from 1000 meters below sea level(aka the midnight zone). Females are known as flabby whalefishes, Males are known as bignose fishes, and juveniles are known as tapetails.

Cetomimidae

Worldwide

Smaller fish, Crustaceans

Animal Type

deep-sea cetomimiform fish

Size

20 centimeters

Depth

from 1000 meters to 3500 meters.

Table of Contents

Where Do They Live:

Found at remote depths starting from 1000 meters to up to 3,500 meters. They have circumglobal distribution.

Classification And Taxonomy:

Tapetails are the young whalefish, while the female is called whalefish and the male is bignose.

Whalefish Appearance and Size:

They have poor eyes, underdeveloped and small—in fact, they lack lenses and are not even capable of forming images. They have a red color like most deep sea creatures. Plus, to help them detect prey, they have sensory pores running over the head to the length of the body. They can reach 20 centimeters, have large mouths, and their dorsal and anal fins are set far back of the head. The pores give the fish a crocodile appearance. They have a distensible stomach allowing them to each much larger prey!

Diet Of The Whalefish:

They eat Crustaceans, and other fishes from the upper zone(the mesopelagic zone) as their habitat is nutrient-poor.

Whalefish Behavior and LifeSpan:

Like other deep sea fishes, they can go night vertical migrations feeding the upper 700 meters above their habitat and returning to the deep by daybreak. Juveniles frequently inhabit shallow waters more than adults. Juveniles also have tapetails called caudal fins.They lack lenses and are not capable of forming images in the deep sea. It has pores helping to detect prey in complete darkness extending from the head to the length of the body placed on the fish’s sides giving the appearance of a crocodile.

Males undergo significant changes as they mature: their jaw bones waste away, mouths shrink, intestines shrivel, and food pipe disappears entirely. Once transformed, males never feed again but rely on a massive liver for sustenance. Tapetails gorge on small crustaceans to develop enormous livers that sustain them as males. Female whalefishes continue to eat throughout their lives and grow to be the largest of the three forms

Reproduction And LifeCycle:

The larvae of tapetails, which are members of the family Mirapinnidae, eventually transform into female whalefish, while the bignose fish are the males of the species.

Cool Facts:

-Female whalefish, also known as Cetostoma regani, are histologically male.

-Tapetails, bignose fish, and whalefish are all members of the same family (Cetomimidae). Tapetails are the young or larvae, while bignose fish are the males.

-This fish is invisible in its habitat as it appears black and stays undetected by prey!

-This fish is not threatened as it inhabits a really deep habitat away from humans!

-There are 30 species of whalefish.

Research About The Whalefish:

All The Collected Specimens were females, leaving the whereabouts of males unknown so scientists concluded that the bignoses, tapetails, and whalefishes are actually different sexes or life stages of the same group of animals. Also, a species of the whalefish called Barbourisiidae was found in new Zealand and Japan.

The whalefish is a master of the deep sea, as this fish hunts in total darkness and is almost blind but its red color does not penetrate through the ocean, so it’s invisible.