Peters’ Elephantnose Fish (Gnathonemus petersii)

The elephantnose fish is a freshwater fish native to the rivers of West and Central Africa. Their trunk-like protrusion is an extension of the mouth that is covered with sensitive electroreceptors. The fish is able to use these receptors, along with a weak electrical field that it generates through muscular contractions, to find hidden prey and navigate in low visibility conditions.

© Sullivan, John P, Bjoertvedt

Banjo catfish
Banjo catfishes get their name from their round, flattened body and long tail. They are dispersed throughout the major rivers of South America.
LHG Creative Photography on Flickr

Banjo catfish

Banjo catfishes get their name from their round, flattened body and long tail. They are dispersed throughout the major rivers of South America.

LHG Creative Photography on Flickr

rhamphotheca:

Mouth Vision: Blind Cave Fish Suctions Water to Navigate :O
by Laura Poppick
The Mexican blind cavefish does not have eyes, but it can “see” obstacles in dark caves by puckering its mouth and producing bursts of suction, according to a new study. The research describes this unique form of navigation for the first time.
Scientists previously thought the eye-less Mexican cavefish navigated by sensing changes in water pressure produced by waves sent off from the fish’s own body.
But when the researchers examined the fish, they found some problems with this explanation. For example, larger fish, which would presumably produce larger waves, should be able to identify objects from farther away than smaller fish. In fact, larger fish detected objects at about the same distance as smaller fish did…
(read more: Live Science)
photograph by Gregory Zilman

rhamphotheca:

Mouth Vision: Blind Cave Fish Suctions Water to Navigate :O

by Laura Poppick

The Mexican blind cavefish does not have eyes, but it can “see” obstacles in dark caves by puckering its mouth and producing bursts of suction, according to a new study. The research describes this unique form of navigation for the first time.

Scientists previously thought the eye-less Mexican cavefish navigated by sensing changes in water pressure produced by waves sent off from the fish’s own body.

But when the researchers examined the fish, they found some problems with this explanation. For example, larger fish, which would presumably produce larger waves, should be able to identify objects from farther away than smaller fish. In fact, larger fish detected objects at about the same distance as smaller fish did…

(read more: Live Science)

photograph by Gregory Zilman

astronomy-to-zoology:

Goldfish (Carassius cenularisustergum)
…a small species of cyprinid fish that is endemic to a wide variety of mountain lakes in Switzerland. A collector in the United States had introduced a captive population in 1937 into a lake in her Connecticut property but, after a unfortunate series of ecological events the population of C. cenularisustergum had escaped and has become an invasive species in a number of countries around the world. Goldfish are highly adaptable and can occupy a wide range of habitats across the globe, which has lead to their reproductive success worldwide. Like other members of the genus Carassius goldfish are often seen in large groups (known as a “bag”) with individuals packed as close together as they can. The exact reason for this behavior is still unknown but it is thought that this is done to prevent predators from singling out an individual to eat. However, some experiments disprove this theory, stating that predators will attempt to eat as many of the small fish as possible, and that congregating would not heighten an individual’s chances of survival.
Due to their cosmopolitan distribution C. cenularisustergum is preyed upon by a large number of predators, from all walks of life. Their main predator is humans (Homo sapiens) which will farm  the small cyprinids by the millions. By using a special devise known as a Pepperidge Farm. Even though they are harvested in millions, farming had no significant effect on their population as C. cenularisustergum has a high reproductive rate, with individuals capable of producing thousands of young in special nests known as “Cartons”. C. cenularisustergum is sometimes known as the “smiling fish” due to its wide gape, it uses this wide but thin mouth to efficiently graze on algae that grows on smooth rocks.
Classification
Animalia-Chordata-Actinopterygii-Cypriniformes-Cyprinidae-Carassius-(cibum)-C. cenularisustergum
Image: Kenzie

astronomy-to-zoology:

Goldfish (Carassius cenularisustergum)

…a small species of cyprinid fish that is endemic to a wide variety of mountain lakes in Switzerland. A collector in the United States had introduced a captive population in 1937 into a lake in her Connecticut property but, after a unfortunate series of ecological events the population of C. cenularisustergum had escaped and has become an invasive species in a number of countries around the world. Goldfish are highly adaptable and can occupy a wide range of habitats across the globe, which has lead to their reproductive success worldwide. Like other members of the genus Carassius goldfish are often seen in large groups (known as a “bag”) with individuals packed as close together as they can. The exact reason for this behavior is still unknown but it is thought that this is done to prevent predators from singling out an individual to eat. However, some experiments disprove this theory, stating that predators will attempt to eat as many of the small fish as possible, and that congregating would not heighten an individual’s chances of survival.

Due to their cosmopolitan distribution C. cenularisustergum is preyed upon by a large number of predators, from all walks of life. Their main predator is humans (Homo sapiens) which will farm  the small cyprinids by the millions. By using a special devise known as a Pepperidge Farm. Even though they are harvested in millions, farming had no significant effect on their population as C. cenularisustergum has a high reproductive rate, with individuals capable of producing thousands of young in special nests known as “Cartons”. C. cenularisustergum is sometimes known as the “smiling fish” due to its wide gape, it uses this wide but thin mouth to efficiently graze on algae that grows on smooth rocks.

Classification

Animalia-Chordata-Actinopterygii-Cypriniformes-Cyprinidae-Carassius-(cibum)-C. cenularisustergum

Image: Kenzie

rhamphotheca:

The American paddlefish, Polyodon spathula
… is a paddlefish living in slow-flowing waters of the Mississippi River drainage system. It appears to have been extirpated from Lake Erie and its tributaries. They are closely related to the sturgeons.
This large Chondrostean freshwater fish may grow to 220 cm (7 feet) and weigh up to 100 kg (220 lbs). The paddlefish takes its common and scientific names from its distinctive snout, which is greatly elongated and flattened into a paddle shape. The American paddlefish is believed to use sensitive electroreceptors on its paddle to detect prey, as well as to navigate while migrating to spawning sites. It feeds primarily on zooplankton but also feeds on crustaceans and bivalves…
(read more: Wikipedia)
illustration by Timothy Knepp, USFWS

rhamphotheca:

The American paddlefish, Polyodon spathula

… is a paddlefish living in slow-flowing waters of the Mississippi River drainage system. It appears to have been extirpated from Lake Erie and its tributaries. They are closely related to the sturgeons.

This large Chondrostean freshwater fish may grow to 220 cm (7 feet) and weigh up to 100 kg (220 lbs). The paddlefish takes its common and scientific names from its distinctive snout, which is greatly elongated and flattened into a paddle shape. The American paddlefish is believed to use sensitive electroreceptors on its paddle to detect prey, as well as to navigate while migrating to spawning sites. It feeds primarily on zooplankton but also feeds on crustaceans and bivalves

(read more: Wikipedia)

illustration by Timothy Knepp, USFWS

rhamphotheca:

The Devils Hole pupfish (Cyprinodon diabolis) is an icon of the conservation movement,” says Darrick Weissenfluh, a U.S. Fish and Wildlife Service biologist who is leading an effort to save the exceedingly rare and endangered fish at a facility within Nevada’s Ash Meadows National Wildlife Refuge. 
Read more:  http://go.usa.gov/KTC5
Photo credit: Olin Feuerbacher
(via: USFWS National Wildlife Refuge System)

rhamphotheca:

The Devils Hole pupfish (Cyprinodon diabolis) is an icon of the conservation movement,” says Darrick Weissenfluh, a U.S. Fish and Wildlife Service biologist who is leading an effort to save the exceedingly rare and endangered fish at a facility within Nevada’s Ash Meadows National Wildlife Refuge.

Read more: http://go.usa.gov/KTC5

Photo credit: Olin Feuerbacher

(via: USFWS National Wildlife Refuge System)

Waterfall Climbing Cave Fish (Cryptotora thamicola)
Also known as the cave angel fish, this species has only been found in subterranean caves within the Pang Mapha karst system in Thailand. The fish has been observed climbing up a small waterfall, using its fins to grasp the rock and resist being swept away by the fast moving waters. Having evolved in darkness, the species has lost body pigmentation and its eyes.
© Chulabus Khatancharoen via Flickr

Waterfall Climbing Cave Fish (Cryptotora thamicola)

Also known as the cave angel fish, this species has only been found in subterranean caves within the Pang Mapha karst system in Thailand. The fish has been observed climbing up a small waterfall, using its fins to grasp the rock and resist being swept away by the fast moving waters. Having evolved in darkness, the species has lost body pigmentation and its eyes.

© Chulabus Khatancharoen via Flickr