Ghost Fish: Characteristics, types, habitat and more….

Do ghost fish exist? Probably not!  However, In July 2016, a fish that is presumed to belong to the Aphyonidae family was seen near the Mariana Trench in the Pacific Ocean. Given its curious anatomy it was called ghost fish.

The Ghost Fish’ Story

The images of this fish were captured with the help of the Deep Dicovererer underwater robot of the Okeanos Explorer, in one of the expeditions of the National Marine Fisheries Service (NMFS) and the National Oceanic and Atmospheric Administration (NOAA), agencies of the United States dedicated to the study of the oceans and fishing.ghost fish: Okeanos Explorer

«I’m sure it’s an Aphyonidae and it’s the first time a fish in this family is seen alive,» said Bruce Mundy, the fishing biologist at the government agency in charge of the expedition. «This is really something unusual,» he said.

Mundy also indicated that fish belonging to the Aphyonidae family had only been found dead, after being caught from the depth by fishermen or scientists and taken to the surface.

Very few details are known about the living, feeding and reproduction conditions of these unique deep-sea fish.

The same robot of the Deep Dicovererer submarine got, in February of the same year, the first images of an octopus that also looked spooky, familiarly known as Casper, in Hawaiian waters. It’s  worth mentioning that the depth of the Mariana Trench is about 11,000 meters, much more than the height of Everest from sea level (8,848 meters above sea level).

The ghost fish video was presented by NOAA on Friday, July 2 on its YouTube channel, which includes other videos about its explorations around the world. The recording had about 70 thousand views, to the astonishment of the spectators and scientists.

With this it’s  shown that there is much to explore underwater, who knows how many fish similar to this “ghost” specimen hide there below?

Here it’s


More Information about the Ghost Fish’ (Aphyonidae) family

Most of the specimens found in the Aphyonidae family have been accidentally captured during trawling or dredging operations, Mundy said.

«There has been a great debate about whether these fish are pelagic, they live in the water column or if they are associated with the ocean’s bottom, like this one,» he said.

The observation of the ghostly fish that flutter along the ocean floor doesn’t solve the question, he said, but provides the first evidence that suggests that these fish are inhabitants of the bottom.

«Our interns think that this fish looks like Falkor, a dragon from ‘The Neverending Story,’» said Shirley Pomponi, leader of the biological sciences team at the deep-water exploration project, in the video published by NOAA.

Learning about the Aphyonidae family

Aphyonids are the Aphyonidae family of marine fish included in the order Ophidiiformes, distributed throughout the Atlantic, Indian and Pacific Ocean. Their name derives from the Greek “aphyo”, which means sardine, by its similar color.


The Aphyonids’ skin has no scales; they have no swim bladder, which is indicative of their sedentary habits.  The dorsal, caudal and anal fins are fused into a single thin fin that surrounds the entire back of the body.

Their eyes are small and rudimentary; they can have a pointed spine in the operculum and their pelvic fins are formed by a single unique radius.

Habitat and Bevavior.

The Aphyonids live on the seabed, (most below 700 m deep) characterized by being viviparous species, who take great care of their young.

Let’s watch

Main Divisions of life in the Ocean

Since we have learned about this interesting creature, it is highly recommended to learn about life in the marine habitat. The oceans cover almost three quarters of the earth’s surface.

Life extends to its deepest areas, but photosynthetic organisms are limited to the upper areas where the sun’s rays still penetrate.

The sea has an average depth of 3 km and, except for a relatively small fraction of the surface, it’s  dark and cold. Therefore most of its volume is inhabited by bacteria, fungi and animals, not by plants. There are two main divisions of life in the open ocean: the pelagic (free floating) and the benthic (bottom dweller).

A main component of the pelagic division is plankton (phyto and zooplacton) which  is made up of algae, protists, small shrimp, eggs and larvae of many fish and invertebrates.

The benthic division contains sessile animals, such as corals, sponges, sea anemones, clams and other mobile animals, such as worms, starfish, molluscs, crustaceans and fish.

Types of Marine Biomes

Conditions vary greatly from one part of the ocean to the other; this implies that living things are not the same in all places. Therefore, in the oceans we distinguish different types of biomes with certain characteristics and ways of life.

Coastal Zone

It is a transition zone between the ocean and the land. It is well lit and in it we find algae, mollusks, echinoderms and others.

Neritic Zone

It’ s located next to the coastal area, on the continental shelf, therefore the depth is greater, but it is still well lit. Planktonic and benthic organisms abound in it.

Pelagic Zone

It is the furthest from the coast, and it is made-up by: A photic zone or illuminated area in which we find algae and fish and an aphotic zone that in turn is divided into batial and abyssal; lacking light so there isn’t vegetation in it..

The Life in the Pelagic Area

Among the pelagic beings two categories can be considered.  One of them includes those that are passively dragged by the waters’ activity since they float in them, although sometimes they are endowed with weak locomotion appendages, insufficient to oppose the action of currents, waves or winds.

The other is made-up by those who have adequate means to fight and overcome these factors by having swimming organs capable of counteracting them. The former are considered strictly plankton’s builders and, the latter, the necton.

It’s not enough to consider as pelagic animals all those that are susceptible to swimming.

Many fish, such as soles , rays and certain octopuses, are effectively able to swim and even move hundreds of meters above the bottom.

However, their life is so linked and depend  on such area that it would be inappropriate to include them as pelagic animals.

There is no other resource but to limit the beings that form the pelagic domain to those that are characterized by their biological independence from the ocean’s bottom, and even then, and despite the extent of this limitation, many doubts are frequently offered to determine whether A species is pelagic or not.

In many cases, the same species goes through periods of its life as part of the pelagic domain, while in others it is clearly the bottom.

Benthic Zone

The benthic zone is the ecological region at the lowest level of a body of water, such as an ocean or lake, including the surface of the sediment and some layers of its surface.

The organisms that live in this area are called benthos. The community of benthic invertebrates includes crustaceans and polyquettes.

Organisms generally live in close relation to the bottom of the substrate and many are permanently attached to the bottom.

The superficial layer of the soil that covers any water body,(the benthic boundary layer), is an integral part of the benthic, as it greatly influences the biological activity that takes place there.Examples of contact floor layers include sand bottoms, rocky outcrops, coral and bay mud.

Description and Types

The ocean benthic region begins on the coast line (intertidal or eulattoral zone) and extends downward along the surface of the continental shelf towards the sea. The continental shelf is a gently inclined benthic region that extends away from the land mass.

At the edge of the continental shelf, (about 200 meters deep), the gradient increases greatly and is known as a continental slope. The continental slope descends to the bottom of the sea.

The bottom of the sea’s depths is called the abyssal plain and is usually about 4,000 meters deep. The ocean floor is not flat, but it has underwater ridges and deep ocean icy pits known as the fairy zone.

By way of comparison, the pelagic zone is the descriptive term for the ecological region above the benthos, including the water column to the surface.

Depending on the body of water, the benthic zone may include areas that are only a few inches under water, such as a stream or a shallow pond, or it may be at the bottom of an ocean under a 4,000-meter (13,000-foot) column of water.

The benthic habitats are very diverse, depending on their depth and location, and have different biological, physical and geochemical characteristics).

The surface layer of the soil that covers the given body of water is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there.

Examples of contact floor layers include sand bottoms, rocky outcrops, coral and bay mud.

Marine benthic environments are divided into zones according to their depth. From the shallowest to the deepest, these include

    • Coastal and estuarine areas (less than 200 meters deep)
    • The batial zone (200 to 2,000 meters)
    • The abyssal area (2,000 to 6,000 meters)
    • The fairy zone (more than 6,000 meters deep)

Estuarine and near shore benthonic habitats include coral reefs, seaweed forests, crustacean beds, shallow submerged marshes, hard-bodied rocky habitats, and undulating sands.

The abyssal area of the pelagic zone, 2,000 to 6,000 meters deep, remains in perpetual darkness and never receives daylight.

It contains the deep benthic communities near the bottom of the oceans.

It usually has temperatures around 0 to 3ºC, but 13-15ºC in the Mediterranean Sea. Abyss is a Greek word meaning bottomless sea.

The deeper bottoms than the abyssal zone occupy the fairy inhabited hadal zone, whose name comes from Hades, the classical Greek underworld. The lower areas located at depths lower than the abyssal zones occupy the batial zone.

These three zones belong to the area of the sea depths. The hadal, abyssal and batial areas are so deep and at such high-pressure that they and their organisms are difficult to observe and map.

Deep trenches or fissures that sink thousands of feet below the ocean floor, for example, mid-oceanic trenches such as the Mariana Trench in the Pacific are almost unexplored.

Only the Trieste bathyscaphe and the Kaiko remote-controlled submarine have been able to descend to these depths.

Let’s watch

Benthic Organisms

Benthos are organisms that live in the benthic zone and are different from those in other parts of the water column. Many have adapted to live on the substrate (below). In their habitats they can be considered as dominant creatures, but they are often a source of prey for Carcharhinidae, such as the lemon shark.

Many organisms adapted to deep water pressure, aren’t able to survive in the upper parts of the water column. The pressure difference can be very significant (around one atmosphere per 10 meters of water depth).

Since light does not penetrate very deeply into ocean water, the energy source for the benthic ecosystem is often organic matter from the top of the water column moving into the depths.

This dead and decaying matter supports the benthic food chain, where most organisms are scavengers or detriveivores. Some microorganisms use chemosynthesis to produce biomass.

Benthic organisms can be divided into two categories depending on whether they make their home on the ocean floor or an inch or two at the bottom of the ocean. Those who live on the surface of the ocean floor are known as epifauna.

Those who live buried at the bottom of the ocean are known as infauna. Extremophiles, including piezophiles, who thrive at high pressures, can also live there.

These organisms generally live in close relation to the bottom of the substrate; many of these beings are permanently attached to the bottom.

Many organisms adapted to deep water pressure cannot survive in the upper parts of the water column.  The pressure difference can be very significant (around one atmosphere per ten meters of water depth).

Classification Of Benthos

Benthos can be classified in several ways. A division classifies primary producers (algae, aquatic plants) that live in the bottom as «phytobenthos» and all consumers (protozoa and benthic) who live at or near the bottom as «zoobenthos».

The term epibenthos is used for organisms that live on top of the sediment and hyperbenthos for those who live just above the sediment.

These dimensions vary from researcher to researcher, with some of them using a 45-m limit between meiobenthos and microbenthos and some even a tenth of a millimeter.

For example, some define meiobenthos as organisms that can pass through a one-millimeter mesh but will be retained by a 45-mm mesh.

Whether an organism will pass through a one mm mesh will also depend on whether it is alive or dead at the time of classification.

Large invertebrate benthic organisms, which may be known as macrobentos, macrozoobentos or macroinvertebrates (NABS 2008), include marine examples such as starfish , oysters, clams, sea cucumbers, starfish and sea anemones(int), as wells as examples of freshwater such as snails, crayfish(int), and the larvae of many aquatic insects (dragonflies, ephemera, caddisflies).

A microscope is required to see microbentons, including diatoms, bacteria and ciliates (NHPTV 2008). The term meiobenthos was first employed in 1942 by M.F. Mare, but the organisms that would fit into the meiofauna category have been studied since the 18th century. They may include some sea spiders, sea worms and water bears.

The benthic fauna is very diverse. Smith (1996) notes that the composition and diversity of the fauna increases with depth to the middle or lower batial region, then decreases towards the abyssal plain.

Lower organisms tend to have four feeding strategies (Smith 1996): filtration of suspended water material (e.g. coelenteratos), collection of material that has settled on the surface of the sediment (e.g. sea cucumbers ), feed tank (e.g. polyshers) and predators (e.g. fragile stars).

let’s watch one of them

Other fish species called Ghost Fish

This is not the only species nicknamed as ghost, so let’s meet some others.

Black Ghost Knife Fish (Apterolotus albifrons )

This fish commonly known as a black ghost knife fish is native to Venezuela with waters ranging from 23oC to 28oC. It usually inhabits in selvatic streams or in the river grasses and can also be found in streams of rapid currents, very sensitive to environmental changes.

Apterolotus albifrons tends to be an omnivorous fish, which has a low level of difficulty for reproduction in captivity. Males tend to be larger and their tail longer.


This is a fish of nocturnal habits and a peaceful behavior, although they sometimes may become aggressive against small fish such as neon. During day they usually lay on their side at the bottom of the aquarium. .

Feeding Black Ghost Knife Fish

They are not simple to feed asthey generally don’t not food in scales, granules or freeze-dried. During the first few days in a new aquarium must have abundant live prey that can be gradually replaced by frozen foods until they end up accepting the latter without problems.

It’s is normal that several weeks go by without trying the frozen ones, being able to get not fed if they do not feel totally comfortable in the aquarium, so it’s  very necessary to adapt the tank to their needs to avoid these problems.

Black Ghost Knife Fish’ Reproduction

Oviparous. They reach sexual maturity at three years of age. The system is as follows: several adult individuals (more than 5) must be kept in the tank at a temperature of 23ºC while the water level of the aquarium is lowered on the successive days.

When it reaches the minimum level the temperature must be raised to 28oC, as well as the water.

This way you can stimulate the laying. During this period, abundant live prey must be supplied to the parents.

Keep in mind that the couple may become very aggressive with the other tank mates even killing them if the aquarium is not large enough or lacks the necessary shelters.

Suitable aquarium.

The aquarium intended for the ghost fish must meet the conditions for any nocturnal fish of quiet habits to ensure its well-being. About 200 liters for a single specimen will suffice.

It is strictly necessary to arrange a large number of solid ornaments (plants, caves, rocks, logs and so on) so that they can hide during the day, avoiding those that have sharp edges to prevent damage to their delicate skin.

The Black Ghost Knife Fish’ black color implies that the substrate must be the same color, and the lighting must be dim or sifted by floating plants.

They don’t strive in strong water currents but need good oxygenation. The temperature should be maintained between 25 and 30 ºC, the pH between 5 and 7 and the hardness should be less than 10 ºdGH.

Black Ghost Knife Fish’ don’t adapt well to values outside these intervals, easily getting sick in these cases.

Nitrate, nitrite and ammonia rates should always be kept below 50, 0 and 0 ppm respectively.

In addition, it’s good to keep in mind that they are very sensitive to stress, suffering if they do not have enough hiding places, if the light is too intense, if the water is too moving or if the water parameters or the rates of contaminants are not adequate. They are easily attacked by skin parasites (especially white dot) due to the fragility of their scales.

Let’s enjoy them

Black Ghost Tetra (Hyphessobrycon megalopterus)

This is a kind of small, quite popular Characid commonly known as Black Ghost Tetra. Hyphessobrycon megalopterus has a laterally compressed rhomboid body.

Its base color is dark gray dotted with iridescence. Its fins are large compared to the size of its body and extraordinarily developed. In terms of body’s color it’s mainly black although the fat fin and the pectorals may have some reddish tones.

Yet, the hallmark of the species corresponds to the vertical black spot surrounded by white iridescence behind the gills.

Their common denomination of black ghost is related to the loss of color that they display when the lighting goes out.  Under these conditions their body becomes partially transparent grayish.


Small species reaching a maximum of 4’5 cm.


This species is native to South America and can be found in various locations on the border between Bolivia and Brazil. They live in calm waters and in a much planted backwater.

Aquarium Length

Due to its small size and gregarious character it will be enough to keep ghost tetras in aquariums from 50 or 60 liters.

Water conditions

Hyphessobrycon megalopterus adapts to various aquatic conditions. Preferably acidic but that can fluctuate between 6 and 7.2º Ph.


Tetra ghost fish should be kept in a temperature range between 23º to 27º C, Since Temperatures above 27 C will make them aggressive, a characteristic that we can detect by the tears of the fins produced by the bites.


This species doesn’t require a very complicated maintenance but it should be taken into account that the aquarium should be sparsely populated and that it must have large vegetation in the back and sides, leaving a large space for swimming in the frontal portion..

Employing roots and logs will benefit the maintenance of an acidic Ph in addition to contributing to partially dye the water in amber which will transmit a higher level of naturalness.  Moreover, it’s good to take into account that employing a dark substrate will allow the species to intensify its coloration

Feeding Tetra Ghost Fish

This is an omnivorous species that will accept any type of food. However, a rich and varied diet combining frozen, lyophilized and flake foods will be enough to cover their needs.

Sex differences

The main difference is given by the size of the dorsal and anal fins in males. Older specimens may have fins’ lengths even larger than their body size. So, their color is more intense and the body’s height is greater.

The females, in addition to being more stylized and with shorter fins, have reddish tones in the pectoral and adipose fins.


Reproducing ghost tetras in aquariums is viable although some mishaps might occur. . Small volumes of 40 or 50 liters will be enough. After detecting a possible partner you should separate them for about a week. Feeding them abundantly.

Keep in mind to employ a substrate made-up by marbles and some fine leaf plants. The water should be extremely soft and slightly acidic with a temperature no higher than 28ºC.

Once the separation time has elapsed, the female should be introduced first and two days later the male.

The implementation must take place at dusk removing the parents from the aquarium on next day, so they do not devour their own eggs.

The larvae hatch approximately after 48 hours and successively over several days. After hatching, and after four days, after having absorbed the yolk sac, proceed to feed with commercial preparations for fry.

Let’s watch them


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