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

Drought Resistant Killifish (Nothobranchius geuntheri depicted)
The genus Nothobranchius are a group of freshwater fish that live in the mud pools of the African plains. These pools are only filled throughout the rainy season and dry up seasonally. As an adaptation to this extreme environment, the fish have evolved an extremely fast maturity rate and produce eggs that resist the dessication of their environment.
 Their eggs have the amazing ability to withstand being dried out. They lay in a state of diapause, resting periods when development ceases, over the time when their pools are dry. When the rain finally comes, a series of biochemical messages causes the eggs to resume development. These young fish must race to mature and breed before their pools dry out again in a couple of months.
Adilson Borszcz via Flickr

Drought Resistant Killifish (Nothobranchius geuntheri depicted)

The genus Nothobranchius are a group of freshwater fish that live in the mud pools of the African plains. These pools are only filled throughout the rainy season and dry up seasonally. As an adaptation to this extreme environment, the fish have evolved an extremely fast maturity rate and produce eggs that resist the dessication of their environment.

 Their eggs have the amazing ability to withstand being dried out. They lay in a state of diapause, resting periods when development ceases, over the time when their pools are dry. When the rain finally comes, a series of biochemical messages causes the eggs to resume development. These young fish must race to mature and breed before their pools dry out again in a couple of months.

Adilson Borszcz via Flickr

Bubble Eye Goldfish  (Carassius auratus auratus)
Goldfish have been selectively bred for hundreds of years, resulting in a wide variation in morphology. The popular ornamental fish was first domesticated from wild carp in China, where orange mutations of the normally silver fish were recorded in the Jin Dynasty (265 - 420). 
In the Tang dynasty (618 - 920), carp were commonly kept in ornamental ponds and were selectively bred for a gold mutation. By the Song Dynasty (920 - 1279), the domestication of goldfish was firmly established. 
Today, there are about 300 distinct breeds recognised in China. Some popular varieties include features such as the bubble eye, telescope eyes, fancy tails and a compressed body. Many of these features provide significant disadvantage for the fish and as such, specialist care is needed to successfully raise and breed them. 
Jordan Hartig on Wikimedia Commons

Bubble Eye Goldfish (Carassius auratus auratus)

Goldfish have been selectively bred for hundreds of years, resulting in a wide variation in morphology. The popular ornamental fish was first domesticated from wild carp in China, where orange mutations of the normally silver fish were recorded in the Jin Dynasty (265 - 420).

In the Tang dynasty (618 - 920), carp were commonly kept in ornamental ponds and were selectively bred for a gold mutation. By the Song Dynasty (920 - 1279), the domestication of goldfish was firmly established.

Today, there are about 300 distinct breeds recognised in China. Some popular varieties include features such as the bubble eye, telescope eyes, fancy tails and a compressed body. Many of these features provide significant disadvantage for the fish and as such, specialist care is needed to successfully raise and breed them.

Jordan Hartig on Wikimedia Commons

White Cloud Mountain Minnow (Tanichthys albonubes)
The white cloud mountain minnow is a small freshwater fish native to southern China and Vietnam. Despite being extremely common in the aquarium trade, the fish is exceptionally rare in the wild due to habitat degredation. The fish was thought to be extinct in the wild for 20 years in the 1980s. Since then, isolated wild populations have been found.
Public domain image

White Cloud Mountain Minnow (Tanichthys albonubes)

The white cloud mountain minnow is a small freshwater fish native to southern China and Vietnam. Despite being extremely common in the aquarium trade, the fish is exceptionally rare in the wild due to habitat degredation. The fish was thought to be extinct in the wild for 20 years in the 1980s. Since then, isolated wild populations have been found.

Public domain image