Oscar (Astronotus ocellatus)
The oscar fish is a species of cichlid native to South America. It is a popular fish in the aquarium trade, growing up to 45 cm and often perceived as intelligent. Several ornamental strains have been developed, including albino and long finned varieties. 
Elma on Flickr

Oscar (Astronotus ocellatus)

The oscar fish is a species of cichlid native to South America. It is a popular fish in the aquarium trade, growing up to 45 cm and often perceived as intelligent. Several ornamental strains have been developed, including albino and long finned varieties. 

Elma on Flickr

Electric Eel (Electrophorus electricus)
The electric eel is a freshwater fish that is known to produce electrical shocks to stun prey and predators. This species grows up to 2 m in length and has become an apex predator in its South American range.
To generate electricity, the fish has specialised organs along the length of its body. These organs are made up of cells called “electrocytes”, which are able to produce charges of 0.15 V each. The electric eel has 5000-6000 of these cells lined up much like batteries in series to produce a cumulative shock of up to 600 V.
Despite the high voltage, the shock is unlikely to kill an adult human due to its extremely short duration of less than 2 milliseconds.
Brian Gratwicke on Flickr

Electric Eel (Electrophorus electricus)

The electric eel is a freshwater fish that is known to produce electrical shocks to stun prey and predators. This species grows up to 2 m in length and has become an apex predator in its South American range.

To generate electricity, the fish has specialised organs along the length of its body. These organs are made up of cells called “electrocytes”, which are able to produce charges of 0.15 V each. The electric eel has 5000-6000 of these cells lined up much like batteries in series to produce a cumulative shock of up to 600 V.

Despite the high voltage, the shock is unlikely to kill an adult human due to its extremely short duration of less than 2 milliseconds.

Brian Gratwicke on Flickr

rhamphotheca:

American Paddlefish (Polyodon spathula)
U.S. Fish and Wildlife Service  It’s wildlife Wednesday and we are going to talk paddlefish. It is among the oldest surviving fish species in North America. But this ancient fish species has been greatly reduced or extirpated over much of its range. 
Paddlefish can live up to 30 years and grow up to 7 feet long and weigh 200 pounds. The fish’s long, paddle-shaped snout accounts for about one-third of its total body length. The snout helps to stabilize the fish as it swims. 
Close to 50 paddlefish were recently released into Caddo Lake on the Texas-Louisiana border and the river that forms it, Big Cypress Bayou. The paddlefish were raised at the  U.S. Fish & Wildlife Service: Fisheries's Tishomingo National Fish Hatchery in Oklahoma. They are 18 months old, 2-3 feet in length, and have a surgically-implanted radio transmitter that will allow scientists to track the movement of individual fish…
(read more: U.S. Fish & Wildlife Service)

rhamphotheca:

American Paddlefish (Polyodon spathula)

U.S. Fish and Wildlife Service  It’s wildlife Wednesday and we are going to talk paddlefish. It is among the oldest surviving fish species in North America. But this ancient fish species has been greatly reduced or extirpated over much of its range. 

Paddlefish can live up to 30 years and grow up to 7 feet long and weigh 200 pounds. The fish’s long, paddle-shaped snout accounts for about one-third of its total body length. The snout helps to stabilize the fish as it swims. 

Close to 50 paddlefish were recently released into Caddo Lake on the Texas-Louisiana border and the river that forms it, Big Cypress Bayou. The paddlefish were raised at the U.S. Fish & Wildlife Service: Fisheries's Tishomingo National Fish Hatchery in Oklahoma. They are 18 months old, 2-3 feet in length, and have a surgically-implanted radio transmitter that will allow scientists to track the movement of individual fish…

(read more: U.S. Fish & Wildlife Service)

Ocellatus Cichlid (Lamprologus ocellatus)

Lamprologus ocellatus is a species of shell-dwelling cichlid native to Lake Tanganyika in East Africa. In the wild, they inhabit the muddy or sandy shores which are littered with snail shells. These fish have evolved to be associated with snail shells, burying in them in the substrate and use them as shelters.  The fish live in small colonies and raise their young in the protection of the shells.

Elma on Flickr

Alligator Gar (Atractosteus spatula)

Growing up to 3m (10 ft) in length the Alligator gar is the largest species of gar and one of the largest freshwater fish in North America. The primitive fish is able to withstand low oxygen conditions as it is able to breath atmospheric air using a modified swim bladder.

The fish is an ambush predator, lying still in the water as if it were a floating log. Unsuspecting prey, which consists of other fish, small mammals and birds, unknowingly approach the gar. When in striking range, the gar lunges forward, penetrating its prey with its double row of sharp teeth.

The alligator gar has been historically classified as a nuisance, and was indiscriminately hunted in much of its range. As a result, much of its range and population sizes have been reduced.  Nowadays, there are projects to help monitor these fish and help protect them against further endangerment.

Photo by Greg Hume

Spotted Gar (Lepisosteus oculatus)
The spotted gar is a primitive freshwater fish native to North America, from Lake Michigan down to the Gulf Coast. Growing up to 0.91 m (3ft) it is one of the smallest gars, but is a formidable predator nonetheless. An elongated snout lined with sharp teeth allows it to easy snare any fish smaller than itself. 
Chantel Wagner Kornin on Flickr

Spotted Gar (Lepisosteus oculatus)

The spotted gar is a primitive freshwater fish native to North America, from Lake Michigan down to the Gulf Coast. Growing up to 0.91 m (3ft) it is one of the smallest gars, but is a formidable predator nonetheless. An elongated snout lined with sharp teeth allows it to easy snare any fish smaller than itself.

Chantel Wagner Kornin on Flickr

Diamond Tetra (Moenkhausia pittieri)
The diamond tetra is a small freshwater fish found near Lake Valencia in Venezuela. In the aquarium trade, it is popular for its very iridescent scales, which catch and reflect light like crystals. Like many other tetra species, this fish is best kept in a small group.
Elma via Flickr

Diamond Tetra (Moenkhausia pittieri)

The diamond tetra is a small freshwater fish found near Lake Valencia in Venezuela. In the aquarium trade, it is popular for its very iridescent scales, which catch and reflect light like crystals. Like many other tetra species, this fish is best kept in a small group.


Elma via Flickr