Whalefishes Facts

Whalefishes Profile

The creatures of the Deep Ocean is almost certainly where Nickelodeon got their inspiration for the show Aaahh!!! Real Monsters. While marine biologists have yet to find a fish with eyeballs in its hands, more or less everything else is down there. 

One of the deepest-living fishes known to science, found as far as 3,500 m below the surface, is an animal known as the flabby whalefish.

But there are plenty more whalefish where that came from! There are hairy ones, velvet ones and a total of around 32 (disputed) species of whalefishes, each as bizarre as the last, and it appears there’s still a huge amount left to discover about them.

Whalefishes Facts Overview

Habitat:	Deep marine
Location:	Worldwide
Lifespan:	Unknown
Size:	40 cm (16 in) in the largest species, usually closer to 20 cm (8 in)
Weight:	Unlisted
Colour:	Varied: typically red to orange, sometimes with a black body
Diet:	Crustaceans, other fishes
Predators:	Unknown
Top Speed:	Unknown
No. of Species:	32+
Conservation Status:	Not listed

Whalefish are a curious lot that look right at home among most of the other curious lots of the deep. They have elongated bodies with tiny eyes and enormous mouths and while they’re fairly well documented, not much is known about them.

Thought to feed on crustaceans and smaller fish, they float about conserving energy, emitting a feint glow, and living in some of the deepest parts of the ocean, they still keep a lot of their cards close to the chest.

Interesting Whalefishes Facts

1. Nobody knows quite what they are

The order Stephanoberyciformes contains some of the most prehistoric-looking animals you’ll ever see.

The photos of the armoured ridgeheads, for example, look like they were taken in the Cambrian period, or perhaps on Acheron and have no place in a civilised ocean.

This order also contains such equally bizarre animals as the Bristlyskin, the pricklefishes and the gibberfishes, and it’s where some authorities also place the whalefishes, as a suborder within.

But others have given the whalefishes their own order, Cetomimiformes, and tie them closest to their sister taxon of squirrelfish and flashlight fish.

None of this is all that important unless you’re a fish taxonomist, because to look at, they fit right in among all of the the misfits of the deep. They can at least be grouped into three families: the velvet whalefishes, the redmouth whalefishes and the flabby whalefishes. ¹

2. There are three types

The flabby whalefishes are one family in this order, made up of relatively large, deep-living whalefishes found all around the Southern Hemisphere.

The largest whalefish there is lives here, and is a whopping 40 cm long, looking like an enormous tadpole. The hairyfish is also a member of this family, along with the vast majority of accepted whalefish species.

The redmouth whalefishes are, as the name suggests, red. But being scaleless, this makes them look like a product of menstruation – at least, once brought to the surface, as they are also very deep-living fish. There are only two species of these. 

The third family is the velvet whalefishes, and they are made of only a single known species, Barbourisia rufa, which is a lot more elongated and pleasantly orange than its relatives but carries the characteristic gaping mouth that the whole order is known for. 

There is talk of a hidden relationship between the redmouth whalefishes and another order of fishes called the Gibberfishes, and this is the reason for a lot of confusion around the order’s taxonomy. It all comes down to a very unusual organ. 

3. Tominaga’s organ

The gibberfishes are a single genus of similar fishes, with just two known species found in the Atlantic. The largest ever found was about 12 cm long, and while deep-sea fishes, they’re not quite as extreme as the whalefishes, occupying a depth of around 400 metres to a kilometre down. 

What makes them suspiciously like the whalefish, though, is the presence of a mysterious lobed organ known as the Tominaga’s organ, which is found on the front end of the gibbers, and in only one other fish line: velvet whalefishes. 

This odd mass is essentially a lump of white tissue on the fish’s snout, and its purpose is still unknown.

It appears to grow throughout the fish’s life and its lobes sit on either side of the olfactory nerve, and people who’ve dissected these things and know what they’re talking about suggest it’s a secretory organ, though nobody knows what it secretes yet. 

4. Their eyes are rubbish

It’s possible that this organ is a compensatory mechanism for a concerning lack of eyesight. 

While whalefish mouths are enormous, their eyes certainly aren’t, and don’t seem to be able to work very well at all; they don’t even have lenses.

These are fishes who have put all their character points into gulping, which is not uncommon in the deep. Their huge mouths and distensible stomachs allow them to make the most of the largest prey they can find, never knowing when it’ll come along again. 

But eyesight doesn’t appear to be all that important to them. On the other hand, they have a highly developed lateral line, something which most fish have, which is made up of a row of sensory pits down the side of the animal. 

This lateral line is so defined in some species that it’s clearly visible as a stripe, and it will be highly sensitive to changes in water pressure, say, from a charging predator. But they have other defences upstream of this one. ^{2 3}

5. They glow in the dark

This deep-water, blind fish – at least, some species of it – can produce light of its own. Aside from being mostly red, as is common in midwater animals, some species can glow a little in the dark. 

While no light from the surface reaches down to the depths we commonly find whalefish at, there is still light.

Just like this fish, many, if not most, deep sea creatures produce their own, and this creates a very faint background hum that’s enough to outline any schmuck not equipped with their own lighting and a strong silhouette is as good as it gets for a dark water predator, so if you’re prey, it’s best to remove yours. 

By producing faint light to the level of the background glow, animals can camouflage themselves against it. 

6. They begin life in the shallows

Like many deep sea fish, whalefishes don’t begin life in the deep; larvae are thought to spawn in the upper 200 metres of ocean depths, likely where food is easier to come by.

Unfortunately, this also makes them food for a lot more animals, so as soon as they’re ready, they grow up and get down to the relative safety of the deep. 

Once they’re all the way down there, they’re seemingly solitary but being so hard to reach, not a lot is known about them. ⁴

Whalefishes Fact-File Summary

Scientific Classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cetomimiformes
Family:	3 or 4 families

1. JOHN R. PAXTON (2001), “Larvae and Juveniles of the Deepsea “Whalefishes” Barbourisia and Rondeletia (Stephanoberyciformes: Barbourisiidae, Rondeletiidae), with Comments on Family Relationships”, Records of the Australian Museum.
2. “Whalefish”, MBARI.
3. Deep Marine Scenes (2022), “Facts: The Velvet Whalefish”, YouTube.
4. “Whalefish”, Monteray Bay Aquarium.