Shell Castle Cichlid

Male with Females and Shells

Phylum : Chordata
Class : Actinopterygii
Order : Perciformes
Family : Cichlidae
Genus : Lamprologus
Species : L. callipterus

Length : Males 6in (15cm), Females 2.5in (6cm)

IUCN Status : Least Concern

Yesterday afternoon I watched several episodes of the Science Channels "Mutant Planet." One of these, about the lakes in Africa's Rift Valley, featured today's animal, a curious fish sometimes known as the Shell Castle Cichlid.

Lamprologus callipterus is endemic to Lake Tanganyika. These fish exhibit extreme sexual dimorphism; the males can weigh 20 times as much as the females! They are predators that feed off of crustaceans and smaller fish.

I chose this particular Cichlid to feature today because of their interesting breeding behavior. The males are highly territorial and protective of their many, many mates. They gather up old snail shells, sometimes hundreds of them, and bring them into their territory. They then attract nearby females, who then enter these shells in order to lay their eggs. The males then guard over both the females and the eggs until the fry are large enough to leave. At that point neither parent takes any further action in the care of the offspring. Interestingly, the males do not eat at all while they are guarding their "castle." Eventually they become weak and are often chased off by larger, healthier males.

Shell Castle Cichlid

Male with Females and Shells

Phylum : Chordata

Class : Actinopterygii

Order : Perciformes

Family : Cichlidae

Genus : Lamprologus

Species : L. callipterus



Length : Males 6in (15cm), Females 2.5in (6cm)



IUCN Status : Least Concern



Yesterday afternoon I watched several episodes of the Science Channels "Mutant Planet." One of these, about the lakes in Africa's Rift Valley, featured today's animal, a curious fish sometimes known as the Shell Castle Cichlid.



Lamprologus callipterus is endemic to Lake Tanganyika. These fish exhibit extreme sexual dimorphism; the males can weigh 20 times as much as the females! They are predators that feed off of crustaceans and smaller fish.



I chose this particular Cichlid to feature today because of their interesting breeding behavior. The males are highly territorial and protective of their many, many mates. They gather up old snail shells, sometimes hundreds of them, and bring them into their territory. They then attract nearby females, who then enter these shells in order to lay their eggs. The males then guard over both the females and the eggs until the fry are large enough to leave. At that point neither parent takes any further action in the care of the offspring. Interestingly, the males do not eat at all while they are guarding their "castle." Eventually they become weak and are often chased off by larger, healthier males.

Domestic Goldfish

Pearl scale Goldfish

Phylum : Chordata
Class : Actinopterygii
Order : Cypriniformes
Family : Cyprinidae
Genus : Carassius
Species : C. auratus auratus

Length : Up to 12in (30cm)

IUCN Status : Not Listed

Did you know that  Goldfish were one of the first fish species to be domesticated? It happened nearly 1,500 years ago in China, where they took rather plain looking Asian Carp and bred them down. They spread to Japan in the 15th century, and were in Europe by the late 17th. Domesticated Goldfish can now be found all around the world!

There are dozens of different Goldfish varieties, coming in all sorts of shapes and sizes. Orange, black, white, and speckled are all common colors. Tail shape is also highly variable, with some being short and blunt and others growing quite long and flowing.

Shubunkin Goldfish

Did you know that there is a reason why Goldfish nibble at tiny bits of food all day? This is because they don't actually have a stomach in which to store food during digestion. Because of this, they have to eat very small amounts several times a day.

Another interesting fact about these popular fish is that they don't actually have three second memories. This misconception has been debunked by scientists and even by enterprising young Australians. Goldfish have the ability to store and recall information, and are able to recognize food and predators just like any other creature.

Domestic Goldfish

Pearl scale Goldfish

Phylum : Chordata

Class : Actinopterygii

Order : Cypriniformes

Family : Cyprinidae

Genus : Carassius

Species : C. auratus auratus



Length : Up to 12in (30cm)



IUCN Status : Not Listed



Did you know that  Goldfish were one of the first fish species to be domesticated? It happened nearly 1,500 years ago in China, where they took rather plain looking Asian Carp and bred them down. They spread to Japan in the 15th century, and were in Europe by the late 17th. Domesticated Goldfish can now be found all around the world!



There are dozens of different Goldfish varieties, coming in all sorts of shapes and sizes. Orange, black, white, and speckled are all common colors. Tail shape is also highly variable, with some being short and blunt and others growing quite long and flowing.

Shubunkin Goldfish

Did you know that there is a reason why Goldfish nibble at tiny bits of food all day? This is because they don't actually have a stomach in which to store food during digestion. Because of this, they have to eat very small amounts several times a day.



Another interesting fact about these popular fish is that they don't actually have three second memories. This misconception has been debunked by scientists and even by enterprising young Australians. Goldfish have the ability to store and recall information, and are able to recognize food and predators just like any other creature.

Sea Lamprey

Sea Lamprey Mouth

Phylum : Chordata
Class : Cephalaspidomorphi
Order : Petromyzontiformes
Family : Petromyzontidae
Genus : Petromyzon
Species : marinus

Length : 20in (50cm)

IUCN Status : Least Concern

Despite the name, the Sea Lamprey can be found in freshwater areas as well as the sea. They are a parasitic species located in and around the Atlantic Ocean, the Mediterranean Sea, and the American Great Lakes. Some Sea Lampreys spawn in freshwater, but some have made the Great Lakes their home, moving in permanently as invasive species.

Sea Lamprey attached to Lake Trout

The Sea Lamprey is a primitive, cartilaginous fish with an eel-like body. They have circular mouths filled with sharp teeth that they use to latch on to their hosts bodies. The Lamprey saliva also possesses and anticoagulant that makes it very difficult for their host's wound to heal. They allows the Lamprey to feed for much longer. If the host doesn't die first, the Lamprey can stay attached for weeks at a time. Lampreys target many different species, and have few, if any, natural predators.

A few measures have been taken to control the Lampreys in the Great Lakes. One is lampricide, a chemical that kills Lamprey larvae but that has little affect on other fish species. Barriers and sterilization have also helped to reduce the numbers. Lamprey populations in Lake Michigan have reduced by 90% thanks to these tireless efforts.

Electric Eel

(Image Source)

Phylum : Chordata
Class : Actinopterygii
Order : Gymnotiformes
Family : Gymnotidae
Genus : Electrophorus
Species : electricus

Length : Up to 6-8ft (2-2.5m)
Weight : 40lbs (20kg)

IUCN Status : Least Concern

Did you know that despite the name, Electric Eels are more closely related to Catfish then they are to actual Eels? These curious creatures are actually members of an Order known as "Knifefishes" and they are found in the freshwater basins of the Amazon and Orinoco Rivers.

Electric Eels are major predators within their watery domains. Unsurprisingly, this is due to the large amount of electricity that they can release to stun their prey. Their bodies are home to about 6,000 specialized cells known as electrocytes. They store up power than can be discharged quickly at a strength of about 600 volts. While swimming around, Electric Eels emit much lower, 10 volt shocks that help them to navigate and hunt in the murky water. They feed off of fish, invertebrates, reptiles, amphibians, small mammals. Due to their electric nature, they have very few predators of their own.

So are Electric Eels dangerous to humans? There have been some fatalities, but they are not at all common. Repeated shocks can induce heart attacks, while other shocks have lead to paralysis and drowning.

Electric Eels also have the interesting ability to breathe air outside of water. Almost 80% of their oxygen comes from gulping up air at the surface. The rivers that they live in are murky and have low oxygen levels, and this breathing method allows them to survive at their large sizes.

Giant Freshwater Stingray

(Image Source)

The Giant Freshwater Stingray (Himantura chaophraya) is a massive, massive fish found in the tropical river waters of South East Asia and Australia. They can grow to sizes of over 94in across (about 240cm) and the largest specimen caught weighed 1,322lbs (600kg). Even their young are huge! They are an ovoviviparous species whose offspring can measure 13in (34cm) at birth!

Giant Freshwater Stringrays are in fact dangerous to humans, but not because they eat them. These creatures actually feed on small fish and invertebrates. However, as their name might suggest, they have stinging barbs on their tails. These venomous, mucus covered barbs can grow to 15in (38cm) long, and with their whip-like tails, these Stingrays can pierce bone.

These enormous creatures are currently very vulnerable, and all populations are listed as at least that by the IUCN. The Thailand sub-population is Critically Endangered. They faces issues with habitat destruction, fishing, mine-caused silt deposits, and population fragmentation.

Red Bellied Piranha

When pop culture talks about tiny fish that swarm the water and devour everything in sight, they are almost always referring the the Red Bellied Piranha. But interestingly, the reputation of the Piranha as a bloodthirsty killer that will eat a man alive is more or less undeserved. Let's learn why!

(Image Source)

Red Bellied Piranhas (Pygocentrus nattereri) live in the Amazon and in other surrounding coastal rivers in South America. As their name might suggest, they have red coloration on their undersides, and a silvery top.

These Piranhas do have razor sharp, interlocking teeth, and they do sometimes have "feeding frenzies," where a school of them will consume prey and strip it to the bone. But their normal meals includes other fish, insects, crustaceans, and even algae! Don't get me wrong, Red Bellied Piranhas will sometimes feed on much larger creatures, but it's typically because they are sick or injured. In their native habitat, humans are not often bitten by Piranhas, and the Piranhas are often consumed as food!

And despite their aggressive reputation, Red Bellied Piranhas make pretty decent parents. The males and females will protect their nests, and then, after hatching, guard their brood of young for a period.

Angelfish

For some reason whenever I think of fish my brain automatically reverts to strange or colorful deep sea creatures. So when I was brainstorming for an animal today, I made a very conscious effort to look at something of the freshwater variety, and thus today we're going to learn all about Angelfish!

(Image Source)

Angelfish is the common term for species within the Cichlid genus Pterophyllum, but it is also the term given for the specific species Pterophyllum scalare. Their natural habitat is the Amazon River Basin, in the Amazon itself and in other rivers of the surrounding area. They live in water that is highly vegetated, and their color actually depends on the overall clarity of the water. Angelfish are omnivorous.

Angelfish have a very distinct, compressed body shape. They can reach lengths of about five inches, and measure nine to ten inches tall. A mutation known as "veil tail" can add an additional couple of inches. In the wild they are typically silver with black bars, but multiple colors have been bred in captivity. Their shape and coloration work to camouflage them in the wild.

Angelfish have been kept as pets since the 1920s and crossbreeding for specific colors has been a hobby for decades. If you especially interesting in keeping these little guys as pets, check out some of the article links for information about feeding, water quality, breeding, and behavior with other species (they can apparently be none-to-friendly with other types of fish)

Nile Perch

Nile Perch are very large, predatory fish native to a handful of rivers and lakes in Africa, though it has been introduced to others on the continent as well. Lates niloticus is also referred to as Mbuta, Capitaine, and a handful of other monikers. They can grow over 200cm long and weigh over 150kg. Their potential for such large sizes, and thus large cuts of meat, led to their introduction, and has created a large fishing industry.

Image from Tour Egypt

Around 50 years ago, Nile Perch were introduced to Lake Victoria, with the intention that these large fish could be used by everyone who lives around the large lake. The effect on the ecosystem was extremely damaging. The Perch consume anything and everything, and have no real predators besides man. Several species went extinct due to the Nile Perch, and now measures are being taken in other parts of the world to keep these fish out of waterways. They are listed by the IUCN as one of the world's worst invasive species.

Northern Pike

I'm from the Midwest. As a child, I spent a great deal of time in various woodland areas, and have swam in my fair share of Northern Wisconsin and Michigan lakes, and well, two fish in particular always freaked me out from those lakes, the Muskellunge, and the Northern Pike. Northern Pikes live throughout most of the Northern United States, Canada, and most of Northern Europe. They are one of the most widely distributed freshwater fish in the entire world. The European specimens tend to be slightly larger, and overall, Northern Pike can easily reach over 2 feet in length and weigh over 20lbs.They are also capable of living 25 years, with the largest fish obviously being the oldest.

The Face of Terror!
(Image from SACO)

Northern Pike are absolutely voracious eaters, and will attack and consume things that are up to four times their own size. They are aggressive and territorial, and are apparently quite interesting to fish for because they'll try and eat just about anything. This includes human feet, so watch out swimmers! (The bitten toes of a fellow camper when I was 8 or 9 began my dread of these pointy teethed fish) People-feet aside, they normally eat other fish, but ducks, shorebirds, rodents as large as muskrats, and insects are also tasty snacks for the Northern Pike. Heck, they'll even eat other pike. They have sharp, backwards slanting teeth that they continuously replace over their lifetimes.

I haven't done a scientific name derail in a while, but I find the entymology of Esox lucius to be rather fascinating. Esox comes from Greek and Celtic words that essentially mean Salmon, while lucis most likely comes from a Greek word for wolf. Yes. Wolf Salmon. Eater of everything. In fact, besides eating themselves, their only other major predators as adults are human beings. Eggs and young fish are often consumed by other fish, birds and mammals, though obviously a few of those half million eggs laid by each female are able to survive to adulthood.

Thanks again to Jon for the suggestion!

Chinook Salmon

Alaska's state fish, the Chinook Salmon, goes by a plethora of other names, including the King Salmon, Spring Salmon, Tyee Salmon, and Blackmouth Salmon. It is the largest of the pacific salmon, often exceeding 40lbs, and is and extremely important fish for commercial and sporting uses. They are found all along the Pacific coast, from the Bering Strait to Southern California.

Image from Pacific Northwest National Library

Male and female salmon differ in appearance, with the males possessing a hooked upper jaw and nose, some reddish coloration, and a ridged back. Females have a sleeker shape, blunt faces and grey coloring. Coloring in the males and females changes during spawning. The males also develop the hooked face at that time.

Salmon are well known for their breeding practices. In the late summer/early fall, the normally ocean dwelling salmon make for deep, freshwater streams in order to spawn. Young fish (fry) remain in the freshwater environments for around a year before becoming smolt (juvenile fish) and heading out to the saltwater estuaries. The salmon then spend anywhere from 1-8 years in the ocean, before travelling back up river to the place of their birth to spawn. Males and females pair up to breed, and then the female will dig a nesting hole where she will deposit between 3,000 and 14,000 eggs. The males then fertilize the eggs, and both parents stand guard over them to keep them safe from predators. Unfortunately the long migration, sometimes constituting hundreds, if not thousands of miles, followed by the taxing process of spawning, saps all of the adult's remaining energy. Because of this, all Chinook Salmon die during their spawning migrations.

Chinook are valuable not only because of their commercial impacts, but also because of their role as a role source for numerous other species. Whales, bears, seals and birds of prey all consume Chinook Salmon. Habitat loss, over fishing, and waterway development (such as the creation of dams) are all human made threats to the Chinook Salmon. They are endangered in the lower 48 states, but the stocks in Alaska remain healthy.

Alligator Gar

Image from Diobas LTD.

The Alligator Gar (Atractosteus spatula) is North America's largest purely freshwater fish, and is identified by its long, slender body, alligator like snout, and interlocking scales. It's species name, spatula, is Latin for "a broad piece," which pretty much describes its snout, as well as our cooking utensils. They are a member of the class Actinopterygii, fish whose fins are held in place by bony spines, and whose earliest appearance in the fossil record dates back over 400 million years.

They weigh over 200lbs at adulthood and can reach sizes of 10ft. Alligator Gar can be fished for in certain states, and the largest specimens ever angled topped 300lbs. 
Interestingly, the Gar can live outside of water for up to two hours. They are also served up in restaurants and have a good number of recipes devoted to their preparation. Gar themselves feed on other fish, though they may also make meals out of birds and small reptiles. Full grown, they have very few predators besides man.
Alligator Gars have a pretty bad, but probably undeserved, reputation. There have been reports for decades that these fish are dangerous man-eaters, though there is very little evidence of attacks even happening. Jeremy Wade, from the Animal Planet show, River Monsters, hypothesizes that the reputation comes from being mistaken for actual alligators. It is unlikely that they devour people since they like to hold their food in their mouths and carry it with them, something difficult to do with humans.




Edit: I took a visit to the Milwaukee Public Museum today and what did I find right after I bought my ticket...

I apologize for the glass glare! But look at those teeth!

Mekong Giant Catfish

So now we move from a tiny little frog to the largest freshwater fish in existence, Pangasianodon gigas. In 2005, the largest specimen ever recorded was caught in northern Thailand. It was nine feet long and weighed nearly 650lbs. Unfortunately though, she died before being re-released. Anyways, so while one of these dudes could probably swallow a small child with ease, they eat primarily algae that they find on rocks on the bottom of the river, though when they are youngin's they have cannibalistic tendencies! But I think I'm going to stamp herbivore on this one, since after their first year (they can live to be 60!) they exclusively eat plant-type materials. Oh the complications of classification systems. I do not envy taxonomists one bit.

But back to the fish! They are endangered, primarily due to habitat changes (damn those dams!) and overfishing. It is currently illegal to harvest them in Thailand, Laos and Cambodia. However, the river is gigantic and is home to many small villages that are nearly impossible to enforce fishing bans on. Catfish in general are also a major food source to these populations, and are believed to cause good luck.

Projects have be implemented by a number of organizations to save these monster fishes, but due to the elusive nature of the animal (only a few have been captured since 2000), and the large migratory distances it embarks on, spawning sites have never been found, and the exact number remaining in the wild is unknown. Estimates state that the number has declined by 90% in the past 20 years.

Anyway, for more information check out this really great video from National Geographic.



image from nationalgeographic.com