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Description
Habitat: tropical latitudes of South America, channels of Amazon and Hyppolithe rivers.
In Neocene expansion of Atlantic Ocean had caused break of isthmus of Panama and changes in geography of New World. South America is shifted a little bit farther to the south, and the southern extremity of continent is located in zone of seasonal climate with rather cold snowy winter. But the north of the continent is still in zone of equatorial and tropical climate, and the grandiose river systems carrying their waters to Atlantic are stretched here again. Meandering on plains, Amazon river changed its channel many times during the early Neocene. In 25 million years after extinction of mankind the part of former Amazon basin became the basin of Hippolythe – one of former inflows of Amazon.
Huge rivers joining the circuit of inflows and lakes represent the places of rough evolution of freshwater animals. Usually live beings inhabit the top layer of river waters, rich in oxygen and well lighted. Here it is always enough of food – on the surface of water floating plants grow, and the bottom is covered with thickets of rooting hydrophytes. In wide channels, far from riverbanks, in transparent water the microscopic algae expand, giving food to pelagic fishes of various sizes, down to giant boltergillers (Potamocetus spp.).
But life is present not only at the top layer of water. Bottom “floors” of deep river channels are inhabited by creatures eating rests from the table of inhabitants of top layers of water. They live in the world where the sunlight can not penetrate at all, and eat few things, that fall from above. Food chains are short here, and specialization concerns only the way of search of food, but not a kind of the food.
One inhabitant of deep river channels of Amazonia is a strange fish spending more than half of life, standing on head. It is a wattle-walking catfish, the representative of diverse group of fishes characteristic for South America. This fish has rather strange manner of movement – in rest it takes vertical position and stands on head. Eight wattles surrounding mouth of fish are rather elastic, with muscled mobile bases. Their length exceeds length of body of fish including tail fin. On skin of wattles there is a great amount of chemoreceptors, and branchings of lateral line stretch to them. The role of wattles in life of this catfish is great: fish prefers not to swim, but “to creep” on wattles, moving them like spider legs. However the scared fish takes horizontal position and swims away, waving by the whole body. This fish lives in channels of large rivers at the depth over 20 meters, but in rivers which water carries a plenty of suspension and is non-transparent, these fishes live even at five-meter depth. At night these fishes can move to smaller depth in searches of food, but disappear in depth at the dawn.
The length of body of this catfish does not exceed 30 cm from which the flattened head with wide mouth makes about a quarter. Wattles may reach the length of up to 40 cm. Due to the anatomy of jaw bones the mouth of this catfish can extend forward as a tube to the half of head length. The body has cylindrical shape slightly narrowed to tail fin. The swimming-bladder and fat liver give to the body of fish the density close to density of water, therefore wattle-walking catfish appears almost “weightless” under water and wattles easily maintain weight of body of fish. Back fin is strongly shifted forward and its basis is approximately at the same level as pectoral fins. Not disturbed fish is able to swim in vertical position, making wavy movements by back and pectoral fins simultaneously. The moving back forward is carried out due to wavy movements of anal fin which stretches at half of length of fish. Fatty fin is very small and blade-like. In back and pectoral fins there are strong poisonous prickles.
Among senses at wattle-walking catfish senses of smell and touch are most advanced. Wandering on wattles on oozy river bed, fish receives from receptors the complete information on nearby presence of various animals – predators and prey. Sight does not play any significant role for this fish; eyes of adult individuals are underdeveloped. They are capable to distinguish light from darkness and too bright light frightens this fish. Colouring of this catfish is monotonous pale yellow; fins are transparent.
Wattle-walking catfish feeds on benthic invertebrates – crustaceans and to a lesser degree on larvae of insects which are rarer in deep sites of the rivers. The fish feels their presence with the help of receptors developed on wattles. Having defined the location of prey, fish cautiously “flies up” above the bottom with the help of fin movements, attacks prey from above and catches it by single movement of mouth.
Spawning of wattle-walking catfish occurs in pairs. Male involves the female, uttering loud squeaky sounds with the bases of prickles in pectoral fins. This species does not have complex spawning ritual. Male and the female “get acquainted”, touching each other by tips of wattles. During the spawning fishes adjoin stomaches, also keeping vertical position. Female lays eggs on male’s belly and leaves him; spawning repeats up to two times per year. In clutch it may be up to one thousand small eggs. Male bears them about one week, not ceasing to eat. Fry at once leave him, and male does not care of the posterity any more. Fry has other way of life, rather than adult fishes. Young fishes swim in top layers of water and at this time can settle to new habitats. They are almost transparent, and their eyes are normally advanced. They swim in horizontal position, but can hover in thickness of water for a short while, taking vertical position and spreading wattles apart. If the crustacean or fry of other species of fishes touches wattles, they make short throw and catch prey. As young fishes grow, they “settle” on bottom and gradually migrate in deep sites of river channel, being guided mainly by change of light exposure. Fishes of this species become sexually mature at the age of 1 year at length of about 17 cm.

Description
Habitat: tropical latitudes of South America, channels of Amazon and Hyppolithe rivers.
In Neocene expansion of Atlantic Ocean had caused break of isthmus of Panama and changes in geography of New World. South America is shifted a little bit farther to the south, and the southern extremity of continent is located in zone of seasonal climate with rather cold snowy winter. But the north of the continent is still in zone of equatorial and tropical climate, and the grandiose river systems carrying their waters to Atlantic are stretched here again. Meandering on plains, Amazon river changed its channel many times during the early Neocene. In 25 million years after extinction of mankind the part of former Amazon basin became the basin of Hippolythe – one of former inflows of Amazon.
Huge rivers joining the circuit of inflows and lakes represent the places of rough evolution of freshwater animals. Usually live beings inhabit the top layer of river waters, rich in oxygen and well lighted. Here it is always enough of food – on the surface of water floating plants grow, and the bottom is covered with thickets of rooting hydrophytes. In wide channels, far from riverbanks, in transparent water the microscopic algae expand, giving food to pelagic fishes of various sizes, down to giant boltergillers (Potamocetus spp.).
But life is present not only at the top layer of water. Bottom “floors” of deep river channels are inhabited by creatures eating rests from the table of inhabitants of top layers of water. They live in the world where the sunlight can not penetrate at all, and eat few things, that fall from above. Food chains are short here, and specialization concerns only the way of search of food, but not a kind of the food.
One inhabitant of deep river channels of Amazonia is a strange fish spending more than half of life, standing on head. It is a wattle-walking catfish, the representative of diverse group of fishes characteristic for South America. This fish has rather strange manner of movement – in rest it takes vertical position and stands on head. Eight wattles surrounding mouth of fish are rather elastic, with muscled mobile bases. Their length exceeds length of body of fish including tail fin. On skin of wattles there is a great amount of chemoreceptors, and branchings of lateral line stretch to them. The role of wattles in life of this catfish is great: fish prefers not to swim, but “to creep” on wattles, moving them like spider legs. However the scared fish takes horizontal position and swims away, waving by the whole body. This fish lives in channels of large rivers at the depth over 20 meters, but in rivers which water carries a plenty of suspension and is non-transparent, these fishes live even at five-meter depth. At night these fishes can move to smaller depth in searches of food, but disappear in depth at the dawn.
The length of body of this catfish does not exceed 30 cm from which the flattened head with wide mouth makes about a quarter. Wattles may reach the length of up to 40 cm. Due to the anatomy of jaw bones the mouth of this catfish can extend forward as a tube to the half of head length. The body has cylindrical shape slightly narrowed to tail fin. The swimming-bladder and fat liver give to the body of fish the density close to density of water, therefore wattle-walking catfish appears almost “weightless” under water and wattles easily maintain weight of body of fish. Back fin is strongly shifted forward and its basis is approximately at the same level as pectoral fins. Not disturbed fish is able to swim in vertical position, making wavy movements by back and pectoral fins simultaneously. The moving back forward is carried out due to wavy movements of anal fin which stretches at half of length of fish. Fatty fin is very small and blade-like. In back and pectoral fins there are strong poisonous prickles.
Among senses at wattle-walking catfish senses of smell and touch are most advanced. Wandering on wattles on oozy river bed, fish receives from receptors the complete information on nearby presence of various animals – predators and prey. Sight does not play any significant role for this fish; eyes of adult individuals are underdeveloped. They are capable to distinguish light from darkness and too bright light frightens this fish. Colouring of this catfish is monotonous pale yellow; fins are transparent.
Wattle-walking catfish feeds on benthic invertebrates – crustaceans and to a lesser degree on larvae of insects which are rarer in deep sites of the rivers. The fish feels their presence with the help of receptors developed on wattles. Having defined the location of prey, fish cautiously “flies up” above the bottom with the help of fin movements, attacks prey from above and catches it by single movement of mouth.
Spawning of wattle-walking catfish occurs in pairs. Male involves the female, uttering loud squeaky sounds with the bases of prickles in pectoral fins. This species does not have complex spawning ritual. Male and the female “get acquainted”, touching each other by tips of wattles. During the spawning fishes adjoin stomaches, also keeping vertical position. Female lays eggs on male’s belly and leaves him; spawning repeats up to two times per year. In clutch it may be up to one thousand small eggs. Male bears them about one week, not ceasing to eat. Fry at once leave him, and male does not care of the posterity any more. Fry has other way of life, rather than adult fishes. Young fishes swim in top layers of water and at this time can settle to new habitats. They are almost transparent, and their eyes are normally advanced. They swim in horizontal position, but can hover in thickness of water for a short while, taking vertical position and spreading wattles apart. If the crustacean or fry of other species of fishes touches wattles, they make short throw and catch prey. As young fishes grow, they “settle” on bottom and gradually migrate in deep sites of river channel, being guided mainly by change of light exposure. Fishes of this species become sexually mature at the age of 1 year at length of about 17 cm.