Discus Cichlids

Symphysodon aequifasciatus

Today's animal is actually.. well... three animals. There are three species of Discus Cichlids, all of which live in the Amazon River Basin, all of which have compressed, disc-like body shapes, and all of which have some really neat colors and patterns.

There is a little bit of controversy over how the three species are named and identified. There are two general camps, and both agree that there are three different species within the genus, but there is confusion over the classification. One group claims that S. discus  and S. aequifasciatus are close relatives, and a newly discovered species, S. tarzoo, is different due to its spots. Of course, a year after that finding was published another report came out arguing that S. tarzoo is actually S. haraldi, and that Haraldi adn Discus may have formed hybrids.

I'm confused just writing all that. And it doesn't help that these two studies give the same common names for different fish. The Green Discus is apparently both S. tarzoo and S. aequifasciatus! Anyway, for a little more clarity on the great Discus debate, check out this full article.

Discus Fish are popular in aquariums, and their farming has becoming quite a large industry in South Asia. Their bold coloring and interesting shape attract aquarists around the world. They also, like many Cichlids, have an interesting parenting style. While most fish lay their eggs and leave, both Discus Fish parents care for their larvae, even producing a secretion from their skin that their young can feed off of!

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IUCN Status : Not Listed
Location : Amazon Basin
Size : Length up to 10in (25cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Perciformes
Family : Cichlidae -- Genus : Symphysodon

Midas Cichlid

Amphilophus citrinellus

Many of the other Cichlids that we've talked about up to this point live in the African Rift Valley. Today's species is a bit different, and actually hails from the other side of the world-- the San Juan River and nearby waters in Central America.

The Midas Cichlid, as it is often called in the aquatics trade, is a large, hardy freshwater fish that is actually a pretty popular pet, due to their size and coloration. In nature, males have much larger humps than females, though they are only especially large during the breeding season. Those same humps remain year round in captive individuals.

Midas Cichlids are not at all picky about what they eat. In the wild they consume plants, invertebrates, and small fish. In captivity they have a similar diet, and will readily consume vegetation, as well as live and frozen creatures.

One interesting quirk that I discovered is that these fish really like to redecorate! If you keep a Midas Cichlid as a pet, don't put them in a tank with decor that can be easy moved around. The fish will dig up substrate, dislodge plants, and even knock around water heaters and filters!

Keep in mind though, Midas Cichlids can be very aggressive. This behavior is less pronounced when they have more space, so a big aquarium is a must.

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IUCN Status : Not Listed

Location : Central America
Size : Length up to 30in (75cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Perciformes
Family : Cichlidae -- Genus : Amphilophus -- Species : A. citrinellus

Giant Pangasuis

Pangasius sanitwongsei

Meet the Giant Pangasuis, who certainly is one monster of a fish! These dwellers of the Mekong and Chao Phraya River basins can grow nearly 10ft long, and they are second in Catfish size only to the Mekong Giant Catfish. The species is also sometimes referred to as the Paroon Shark and the Chao Phraya Giant Catfish.

In the wild, the Giant Panasuis is a migratory creature, moving upstream in order to spawn just before the monsoon season hits. And when it comes to feeding they are technically omnivores, though they tend to consume meat more often then not. Adults live in the large rivers, while juveniles are found in smaller tributaries.

Unfortunately.. like many large fish in developed areas, they are becoming very, very rare. The Giant Pangasuis is now listed as Critically Endangered. Overfishing, habitat loss, pollution, and capture for the (doomed) pet trade have all been factors for their decline. (I say "doomed" because even though hundreds, if not thousands enter the trade, very few actually live to adulthood, due to their demands, size, and skittish nature that can result in injury.) The Catfish have also had religious rites and ceremonies associated with their capture.

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IUCN Status : Critically Endangered
Location : Southeast Asia
Size : Length up to 9ft (2.75m), Weight up to 660lbs (300kg)

Classification : Phylum: Chordata -- Class : Actinopterygii -- Order : Siluriformes
Family : Pangasiidae -- Genus : Pangasius -- Species : P. sanitwongsei

Japanese Eel

Anguilla japonica

Japanese Eels, sometimes referred to as Unagi, are creatures that live in both fresh and salt water. They can grow to lengths of around 5ft (1.5m), and have quite a remarkable life story! 

As adults, they live in the freshwater rivers of East Asia. But when the times comes to spawn, the eels travel thousands of miles to a spawning ground near the Mariana Islands. They nearly starve in order to make the trip! After the spawning takes place, the eggs are carried off by currents into the open ocean, where the Japanese Eels hatch and grow through their larval phase. As they get larger and larger the ocean current brings them closer to the continent, where they swim upriver just as their parents did and begin the process anew. 

Unfortunately, Japanese Eel populations have been hit hard in recent years. This is because of their high demand within the food industry and because of changes in the ocean environment. These Eels are placed on the Greenpeace Seafood Red List and are listed as “to avoid” on the Monterey Bay Aquarium Seafood Watch. Overfishing, destructive fishing techniques, and damaging capture levels for the captive industry make Japanese Eels (and their culinary name, Unagi) a meal to avoid. 

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IUCN Status : Not Listed

Location : East Asia, Pacific Ocean

Size : Length up to 5ft (1.5m)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Anguilliformes
Family : Anguillidae -- Genus : Anguilla-- Species : A. japonica

Priscacara

Priscacara liops

Priscacara is the name of a now extinct genus of fish that was once abundant over 50 million years ago. Three separate species have been uncovered in fossil form, all within the Green River Formation in the state of Wyoming.

The Green River Formation is a pretty remarkable area, in that it has wonderfully preserved dozens of different early Eocene species. Aside from the Priscacara fish, snakes, crocodiles, birds, and numerous plants have all been found in the Formation.

The three species of Priscacara are actually related to modern Perch, and belong to the same family. They range in size from a few inches to just over a foot, and had round bodies with lower jaws that protruded outwards in order to grab small invertebrates from lake and river bottoms.

Fossils of the Priscacara species are quite common despite their age, and are often sold to collectors for only a few hundred dollars.

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Status : Extinct for around 50 million years
Location : Fossils found in Wyoming
Size : Length up to 13in (33cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Perciformes
Family : Percidae -- Genus : Priscacara

Alewife

Alosa pseudoharengus

The Alewife is a member of the herring family that was originally found off of the Atlantic Coast. Though they are still exist in that range, over the last fifty years they have become an invasive species in the Great Lakes.

In the 1950s, Alewives used the Welland Canal in Ontario to get around Niagara Falls and enter the Great Lakes. Around that same time, Sea Lamprey also invaded, killing off many of the large prey species that would have normally consumed the Alewives. Lack of predation allowed the species to spread, and they are now most abundant in Lake Michigan and in Lake Huron.

Though they are still abundant in the Great Lakes, the population is more in check than it once was. This is due to the introduction of predator species like stocked Trout and Salmon. Unfortunately, the Alewives still vie for food (mostly zooplankton) with other fish, and have negatively affected other populations because of that competition.

Atlantic Alewives are anadromous, a term that means the fish live at sea, but come into freshwater to spawn. Great Lakes Alewives obviously live their entire lives in freshwater, though they spawn in more shallow areas, depositing up to 12,000 eggs! The larvae hatch after only a week, and the fish can live 6 to 7 years.

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IUCN Status : Not Listed

Location : North America
Size : Length up to 6in (15cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Clupeiformes
Family : Clupeidae -- Genus : Alosa-- Species : A. pseudoharengus

Prussian Carp

Carassius gibelio

If you look closely, and use some imagination when it comes to color, you might just recognize today's animal.

You see, the Prussian Carp, which actually originated in Siberia and not Germany, is the wild ancestor to our domesticated Goldfish. Around 1,000 years ago these fish were selectively bred in China to become the colorful aquarium fish that are so prevalent around the world. Like their domestic progeny, Prussian Carp have also spread from their native habitat, and can now be found in rivers and ponds across Europe and Asia.

Prussian Carp are medium sized members of their family, measuring up to 1.5ft long and weighing up to 6lbs.  They have an omnivorous diet, feeding off of plant matter as well as various small invertebrates.

As adults, the Prussian Carp have a grey, greenish color. But when they are younger they tend to be more golden, which  is where the inspiration for the domestication may have some from.

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IUCN Status : Not Listed
Location : Asia, Europe
Size : Length up to 18in (45cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Cypriniformes
Family : Cyprinidae -- Genus : Carassius -- Species : C. gibelio

Longnose Gar

Longnose Gars can be found throughout the eastern United States, as well as in Canada and northern Mexico. They are often spotted in large, slow moving rivers and lakes. They can also survive very well in brackish waters.

Lepisosteus osseus

Longnose Gars get their name because their snouts are more than twice the length of the rest of their heads. And what's inside those snouts? A long row of teeth! Thought they eat a lot of invertebrates as juveniles, Adult Longnose Gars hunt mainly other fish. They are ambush predators, catching prey on their sharp teeth and then thrashing back and forth to further impale them.

Longnose Gars have an interesting mating system. As many as fifteen males will spawn with a single female at the same time. As the female swims and deposits her eggs (which are sticky and adhere to the river bottoms) the males move along behind her releasing sperm. Gar eggs hatch in as quickly as 3 days, but it will take the young fish either 4 years (if male) or 6 years (if female) to reach sexual maturity. Longnose Gars can live close to 20 years!

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IUCN Status : Not Listed

Location : North America

Size : Length up to 72in (182cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Lepisosteiformes
Family : Lepisosteidae -- Genus : Lepisosteus -- Species : L. osseus

Waterfall Climbing Cave Fish

Cryptotora thamicola

Today's animal is one of those strange, mysterious cave dwellers that is rarely seen by human eyes. Its common name is the Waterfall Climbing Cave Fish, and it does exactly what its name describes! These fish have fins that allow them to climb, and have been founding moving up ledges near small underground waterfalls!

The species has only been found in eight subterranean sites within Thailand's Pang Mapha karst formation. It is believed that they only live within that formation, as it is unknown whether those caves are connected to ones elsewhere.

Like many cave dwellers, the Waterfall Climbing Cave Fish have adapted to their dark surroundings. They have no eyes, and their bodies lack all pigmentation. Because why waste valuable energy on sight and color when it is pitch black anyway? They live in fast moving underground water, and feed off of the small organisms that live within the cave (and they themselves are very small, only about 1in long).

The fish are listed as Vulnerable because they are very, very sensitive to water changes and disturbances within their environment. They also have a small range that happens to be popular with spelunking tourists, so humans could have a detrimental impact on the species as well. Overall they are very rare and are rarely seen.

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IUCN Status : Vulnerable
Location : Thailand
Size : Length up to 1in (2.5cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Cypriniformes
Family : Balitoridae -- Genus : Cryptotora-- Species : C. thamicola

Huchen

Hucho hucho

Today's animal is the Huchen, a freshwater fish also known as the Danube Salmon. These Salmon-family members originated in the aforementioned river basin, but have since spread to other parts of Europe and Morocco. However, even with introductions, the species is still considered Endangered due to habitat fragmentation and pollution.

Habitat fragmentation has had a huge impact on the reproductive cycle of the Huchen. Like their cousins in the west, they need to swim upriver in order to spawn, a process made very difficult by the addition of dams. Furthermore, some populations cannot breed at all, due to high water temperatures (like those introduced to Morocco). Huchen eggs need specific water temperatures in order to hatch.

There have been efforts made to protect the Huchen and their environment, including cleaning up the rivers, placing more regulations on fishing, and restocking.

You can identify a Huchen by their slender, cylindrical bodies, reddish-brown coloration, and dark patches. They feed on other fish, invertebrates, and water dwelling birds and mammals.

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IUCN Status : Endangered

Location : Europe
Size : Length up to 5ft (1.5m)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Salmoniformes
Family : Salmonidae -- Genus : Hucho -- Species : H. hucho

South American Armored Catfish

Corydoras semiaquilus

The South American Armored Catfish gets its name from the visible plates on their sides. Many Catfish species have no scales at all, but this small fish has bony scutes that run the length of their body, giving them a very interesting look (as opposed to the smooth appearance of other members of their Order).

The Amazon Basin of South America in where these fish call home. Like many Catfish, they are nocturnal bottom feeders, using their flat heads and barbels to search for and uncover food. They are very small, usually not growing larger than a few centimeters, which means their prey must also be small-- they consume worms, insects, small crustaceans, and various bits of plant matter.

The species is commonly kept in captivity, and are also referred to as the Peru Black Cory. They are said to be a very peaceful fish that won't bother other tank residents, and they prefer to live in small groups. The fish do best in tanks that have bottoms covered in a small substrate, rather than large rocks (since they dig around to feed).

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IUCN Status : Not Listed

Location : Amazon Basin
Size : Length up to 2.5in (6cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Siluriformes
Family : Callichthyidae -- Genus : Corydoras -- Species : C. semiaquilus

Cephalaspis

Cephalaspis

We've talked about Placoderms before on Animal A Day. Remember? Those armored Devonian fish with gigantic shearing teeth? Well, the now-extinct Placoderms weren't the only Devonian fish swimming around with armor. Cephalaspis did as well, partially as a defensive mechanism against the much larger Placoderms. Their name is actually Greek for "head shield," as they had very large, spade-shaped armored heads.

Cephalaspis is the genus name for four different species of ancient fish. They, along with dozens of other species, belonged to the Osteostraci class (making them Ostracoderms). All Ostracoderms had bony armor, but lacked jaws. They all went extinct at the end of the Devonian, around 360 million years ago.

Cephalaspis in particular only lasted till the early Devonian, around 400 million years ago, and all fossils have been found in what is now Western Europe. They ranged in size from a few inches, to about a foot. These fish were most likely fresh water bottom feeders, since their mouths were located on the bottom side of the head. They may have moved their large heads from side to side, stirring up debris and locating smaller animals to feed on.

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Status : Extinct for 400 million years
Location : Western Europe
Size : Length up to 1ft (30cm)

Classification : Phylum : Chordata -- Class : Osteostraci -- Genus : Cephalaspis

Redtail Shark

Epalzeorhynchos bicolor

Do not let the name fool you! The Redtail Shark is not a shark at all, it is a member of the Carp family! The Shark moniker actually comes from the tall dorsal fin, not from any close relational status.

Redtail Sharks are popular pets due to their vibrant coloration. But did you know that they are critically endangered in the wild? The species is endemic to freshwater rivers in Thailand, and over the last 40 years dams and other man-made obstructions have caused the population to drastically decline. Most Redtails in aquariums are now captive bred in Thailand, and then exported.

Redtail Sharks are omnivorous scavengers that feed on smaller creatures and plant material. In captivity it is advised to keep only one per tank, as they can be aggressive and territorial towards other members of their species. Don't be shocked if they chase or harass other fish as well, and make sure to keep a lid on the tank, they can jump out!

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IUCN Status : Critically Endangered

Location : Thailand
Size : Body Length up to 6in (15cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Cypriniformes
Family : Cyprinidae -- Genus : Epalzeorhynchos -- Species : E. bicolor

Channel Catfish

Ictalurus punctatus

The Channel Catfish is the most common, and most frequently angled, Catfish in North America. Their range stretches from southern Canada to northern Mexico, and they'll live in just about any fresh body of water that provides them with adequate food and water temperature.

You can identify a Channel Catfish by taking a look at its tail. They have very deep forked tails when compared to other Catfish species. They also tend of have dark spots on the top side, though in older fish they may merge together.

Channel Catfish can grow to pretty large sizes over their 40 year lifespan, and the food that they eat changes with their size. As young fish they are more omnivorous, eating small critters and plant matter. But as they grow larger they are more and more carnivorous, eating fish, reptiles, and even birds! The Channel Catfish themselves are preyed on frequently when they are in the egg to juvenile phases, but full grown adults have far fewer predators.

Did you know that Channel Catfish are monogamous, breed only once a year, and are pretty good parents? Males and females pair up before the breeding season begins. When it comes time to mate they will swim with their tails wrapped around each other's heads, which stimulates spawning. Once the fertilized eggs are laid the male chases the female off, but she remains nearby to protect her new offspring from a distance. The male sticks around in a much closer proximity, and eventually helps to feed the juvenile fish when they hatch by thrashing in the mud to loosen food bits into the water. The young fish will be independent from their parents within two weeks. Quite the interesting fish!

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IUCN Status : Not Listed

Location : North America
Size : Weight up to 50lbs (23kg)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Siluriformes
Family : Ictaluridae -- Genus : Ictalurus -- Species : I. punctatus

Walking Catfish

Clarias batrachus

Today we're going to be learning about yet another animal that has entered the pet trade... but with some damaging results.

Walking Catfish in their native environment aren't all that bad. They hail from Southeast Asia, and live in a variety of freshwater habitats. They can even be found in waters that other fish will not tolerate well, like canals, flooded areas, and even in brackish zones.

The common name of this species come from the fact that they can "walk" across land. Their pectoral fins allow them to stay upright while they move outside of the water. The movement is far from graceful, but it does let the fish move between different bodies of water.

Walking Catfish are omnivores, and use their barbels to hunt around for anything and everything. They are generalist feeders, consume plant matter, eggs, small fish, and invertebrates. The Catfish themselves are fished for food in their native range.

Back in the 1960s, individuals in the pet industry decided to bring Walking Catfish to Florida. Fish either escaped or were intentionally released into the wild, and now they are considered a dangerous invasive species. They are hurting local fish farms as well as the native species, due to their ability to move outside of water, their hardy disposition, their voracious appetite, and the fact that they carry Enteric Septicemia (ESC). Since the 1960s they have also moved into a handful of other states as well. It is now illegal to own one of these fish in the United States without a federal permit.

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IUCN Status : Not Evaluated
Location : South East Asia
Size : Length around 1ft (30cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Siluriformes
Family : Clariidae -- Genus : Clarias -- Species : C. batrachus

Boeseman's Rainbowfish

Melanotaenia boesemani

The Boeseman's Rainbowfish is one of the many species in the Rainbowfish family. All are colorful, freshwater fish that are found in Australia and New Guinea.

This particular fish measures only about 4inches in length, and hails from the Western end of  New Guinea. Both males and females have the bright coloration, though males are larger and more vibrant. Their bright colors and ease of ownership make them especially popular for aquarists.

Unfortunately that popularity caused some serious harm to the species. In the 1980's over 60,000 males were exported every month. The high volume of capture bestowed the Rainbowfish with an "Endangered" status with the IUCN. Captive fish now come from fish farms, rather than from nature.

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IUCN Status : Endangered

Location : West New Guinea

Size : Length 4in (10cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Atheriniformes
Family : Melanotaeniidae -- Genus : Melanotaenia-- Species : M. boesemani

Neon Tetra

Paracheirodon innesi

Like yesterday's animal, the Sulphur-crested Cockatoo, today's creature is also popular within the pet industry. In fact, the Neon Tetra is one of the most commonly kept tropical fish out there.

In the wild, these little guys can be found in tropical freshwater rivers of Brazil, Colombia, and Peru. They are found in clear and blackwater areas, but not in whitewater, and are found in groups due to their social, shoaling nature.

Male and females Neon Tetras look identical, though the females sometimes have a slightly rounder shape, where the males are more straight and streamlined. Both sexes sport a shiny blue stripe that runs head to tail, as well as a bold red line that traces down the back half of the body.

Though Neon Tetras hail from South America, most of the fish found in the Pet Trade are imported from Southeast Asian farms where they are bred in captivity.

Many places advertise them as great beginner fish, there are still many considerations to take before owning them. They need to live in groups in order to be happiest, 5 is the minimum, but at least 10 are recommended. And despite the small size they do need a good amount of space- at least 1 gallon per fish. The Tetras are also very sensitive, and need stable water conditions.They are shy and are compatible with many other species, though larger fish will bully them, so it's best to keep them with species that are on the small to medium size. They are also suceptible to Neon Tetra Disease Pleistophora, a parasitic disease that is typically fatal.

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IUCN Status : Not Listed
Location : Peru, Colombia, Brazil
Size : Body Length up to 1.2in (3cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Characiformes
Family : Characidae -- Genus : Paracheirodon -- Species : P. innesi

Bumblebee Cichlid

Pseudotropheus crabro

Cichlids are truly amazing little fish. Their family contains as many as 3,000 diverse species, many of whom evolved in isolated habitats, allowing them to adapt to specific niche needs within that environment.

The Bumbleebee Cichlid is one of those species. Named for the yellow and black bands that run vertically down the body, these small fish have evolved to serve a very specific purpose.

Living exclusively in the Lake Malawi area of east Africa, Bumblebee Cichlids feed on the parasites of other fish. Their primary targets are those that infest the Kampango Catfish. The Catfish, which normally eat Cichlids, leave the Bumblebees alone, as they recognize them as helpers. However, in an interesting twist of events, the Bumblebee Cichlids sometimes feed on the Catfish eggs. When this happens, they change to a murky brown color to snatch at the eggs. Once feeding is complete, they shift back to the recognizable black and yellow.

Male Bumblebee Cichlids use their color changing ability to attract females for breeding purposes. They go jet black and circle the female. Bumbleebee Cichlids are mouthbrooders, like many other Cichlid species.

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IUCN Status : Not Listed

Location : Lake Malawi

Size : Length up to 4in (10cm)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Perciformes
Family : Cichlidae -- Genus : Pseudotropheus -- Species : P. crabro

Megapiranha

Artists rendition of Megapiranha

Meet Megapiranha paranensis, a fish four times larger than it's modern day Piranha cousins! While this creature sounds like something out of a science fiction film, it was in fact a real, living fish that swam waters 10 to 8 million years ago.

We know of Megapiranha only from a jawbone and a handful of teeth! These fossils were first discovered in Argentina in the early 1900s, but weren't actually studied until the 1980s. It wasn't until 2009 that the species itself was officially identified and named.

Megapiranha is interesting not only for its gigantic size, but also for the fact that it may explain why Piranhas have the teeth they have today. Presently we have small, carnivorous Piranhas that have single rows of teeth. But we also have relatives like the Pacu, who are herbivores. Those fish have two rows of teeth. Megapiranha has a single row that is zigzagged, meaning it may have been an intermediary species between the two types.

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Status : Extinct for 8 million years

Location : South America

Size : Length up to 3ft (.9m)

Classification : Phylum : Chordata -- Class : Actinopterygii -- Order : Characiformes
Family : Characidae -- Genus : Megapiranha-- Species : M. paranensis