Around the World Freshwater Fish
Scroll through the species below or click on the link to go directly to a specific animal.
- Clown Loach
- Convict Cichlid
- Giant Gourami
- Koi Carp
- Pink Fin Chalceus
- Striped Leporinus
- Walrus Catfish
Names: Arowana (Osteoglossum bicirrhosum).
Habitats: Freshwater systems in South America and Guyana.
Size: 65-100cm in captivity.
Feed: Carnivores, specialised surface feeders.
Special Features: Can leap almost 2m from the water to pick off insects and birds from overhanging branches.
The head of the Arowana is bony and its elongated body is covered in large, heavy scales, with a mosaic pattern of canals. They can obtain oxygen from air by sucking it into its swim bladder, which is lined with capillaries like lung tissue.
Arowana build nests and protect their young after they hatch, and as mouthbrooders, sometimes hold hundreds of eggs in their mouths. The young can make several exploratory trips outside their parent's mouth to investigate the surroundings before leaving permanently. Arowana are solitary and only entertain company when young.
Names: Clown Loach (Botia macracantha).
Habitats: Native to the islands of Sumatra, Borneo and the Sunda Islands in Indonesia.
Feed: Worms, shrimp, small snails and other plant matter.
Special Features: Clown Loaches make clicking sounds when they're happy.
The Clown Loach is a tropical freshwater fish native to the inland waters of Sumatra and Borneo in Indonesia. Their bodies are whitish-orange to reddish-orange, with three thick, black, triangular, vertical bands.
Its head is relatively large and its mouth faces downward with thick, fleshy lips, and four pairs of barbels. The barbels on the lower jaw are small and difficult to see. Clown loaches make clicking sounds when they're happy or as a type of weapon or warning, or when mating. This sound is produced by grinding their pharyngeal (throat) teeth.
Sometimes Clown Loaches swim on their sides, or upside down, and appear ill, or lie on their sides on the bottom of the tank and appear to be dead. This is normal behaviour. Clown loaches are keen observers of other fish and they observe and react accordingly. If other fish are skittish and hide, Clown Loaches will observe this and might do the same.
Names: Convict Cichlid (Amatitlania nigrofasciata).
Habitats: Native to lakes and streams in Central America, especially Honduras and Nicaragua.
Feed: Crustaceans, small fish, insects, worms, plants and algae.
Special Features: Get their name from the eight or nine black vertical bars on their body, similar to classic prison attire.
When Convict Cichlid breed, the male and female pair off and stay together, claiming their own territory and chasing other fish away. Convict Cichlid are among the few fish that protect and guard their young, nudging them home if they stray.
Sexually mature Convict Cichlids form monogamous pairs and spawn in small caves or crevices, excavating the caves by moving earth from underneath large stones. Females lay the eggs on the upper or side surfaces of the cave to which they stick.
They fan their eggs, moving water with their fins over the clutch to promote oxygen. Eggs hatch about three days after fertilisation. Convict Cichlids can be found at the bottom of the turtle and alligator tanks at the National Aquarium herding hoards of babies.
Names: Giant Gourami (Osphronemus goramy).
Habitats: Freshwater systems in Java (native), Southeast Asia, Australia, Seychelles, Mauritius.
Size: Up to 60cm.
Feed: Crustaceans, insects and plants.
Special Features: Also loves strawberries and cherry tomatoes!
The Giant Gourami is a labyrinth fish, which has a chamber in its head above the gills, used for retaining air. This allows the fish to live in water with low oxygen such as muddy swamps. If prevented from surfacing the Giant Gourami drowns.
Giant Gourami live in swamps and rice paddy fields. They need to take oxygen from the surface and are also farmed for food.
Names: Goldfish (Carassius auratus).
Habitats: Native to freshwater systems in China.
Size: Usually 5-10cm but the biggest Goldfish was believed to be around 48cm.
Feed: In the wild, crustaceans, insects, and various plant matter.
Special Features: Goldfish are the most kept pet in the world.
Goldfish were first domesticated in China more than 1000 years ago. A member of the carp family (which also includes Koi Carp), the Goldfish is native to China. Goldfish vary greatly in size, body shape, fin configuration and colouration.
They might be different in shape, colour and size, but all Goldfish come from the same species and originate from the same parent stock. Different varieties have been developed by in breeding but each new sub species retains a throw-back to the original parent species.
Goldfish have strong associative learning abilities and with their visual acuity can distinguish between individual humans. Owners may notice that fish react favourably to them (swimming to the front of the glass, swimming rapidly around the tank, and going to the surface mouthing for food) while hiding when other people approach the tank. Over time, Goldfish learn to associate their owners and other humans with food, often begging for food whenever their owners approach.
Like many fish, Goldfish are opportunistic feeders and don't stop eating on their own accord. When excess food is available, they produce more waste and faeces, partly due to incomplete protein digestion. Overfeeding can sometimes be diagnosed by observing faeces trailing from the fish's cloaca (excretement outlet).
Names: Koi Carp (Cyprinus carpio).
Habitats: Ornamental fish most commonly kept in Japan.
Size: Up to 75cm, 10 kg
Feed: In the wild ... crustaceans and various plant matter.
Special Features: Can destroy waterways by sucking up the mud along the bottom and killing plants.
Koi Carp are the national fish of Japan. Bred as ornamental fish to be viewed from above, they're well patterned along their backs. Koi Carp are banned in most parts of New Zealand as they're pests, destroying waterways and eating native fish eggs.
Koi Carp are a group of fish that are ornamental varieties of domesticated common carp kept for decorative purposes in outdoor Koi ponds or water gardens. The 100s of Koi varieties are distinguished by coloration, patterning, and scalation. The exact origin of Koi Carp is unclear but they're thought to be a cross between the European Carp and the Goldfish.
Like most fish, Koi Carp reproduce through spawning when a female lays a vast number of eggs and one or more males fertilise them. Nurturing the resulting offspring is a tricky and tedious job, usually done only by Koi Carp breeding professionals. Koi will produce thousands of offspring from a single spawning.
Names: Pacu (Colossoma nigripiuue).
Habitats: Guyana and South America, particularly in the Amazon River.
Size: Up to 90cm, 25kg in the wild.
Feed: Omnivorous – happily hunting smaller fish as well as gathering fruit and nuts that fall into rivers and streams.
Special Features: The Pacu can crack open nutshells with their super-sharp teeth!
As a cousin to the Piranha, when young the Pacu is similar in shape and colour. Pacu even live within schools of Piranha where they're protected, until they start to change colour, then they leave the Piranha school to form schools of their own.
Pacu become much larger than Piranha once they mature. They also have a very different teeth system. Whereas Piranha have pointed, razor-sharp teeth and a pronounced under-bite, Pacu have squarer, straighter teeth like humans, and a less severe under-bite, or a slight overbite.
Names: Pink Fin Chalceus (Chalceus macrolepidotus).
Habitats: South America: Negro and Orinoco River basins and coastal rivers in Guyana, Suriname, and French Guiana.
Size: Up to 20cm.
Feed: Omnivorous – will eat most freshwater life forms as well as earthworms, shrimp and bloodworms.
Special Features: Can jump long distances out of the water.
The Pink Fin Chalceus is a very active and predatory fish with the ability to jump long distances out of the water. Considered as a delicacy, local South American Indians shoot them with bow and arrow, the accepted method of catching fish in jungle rivers.
The Pink Fin Chalceus is a long, laterally compressed fish. Its upper body has rows of large scales while the lower body has much smaller scales. Its back is a brown-silver, flanks silver with green iridescence, while its belly is pink-silver. The fins range from yellow to dark red in colour. The upper part of the iris is yellow to orange.
Names: Piranha (Pygocentrus nattereri).
Habitats: Freshwater – native to the Amazon River system in South America.
Size: Up to 30cm in the wild, smaller in captivity.
Feed: Omnivores – any kind of meat (including humans) but also happy eating vegetable matter.
Special Features: Razor sharp teeth that could take your finger off clean as a whistle!
Piranha teeth are so sharp (like a mouth full of surgical scalpels) and their jaws so strong that they could chop off your finger or toe in an instant – bone and all – with the precision of a butcher's meat cleaver.
Piranha live in large schools (between 30 and 60) and it's these sheer numbers that make them (potentially) man-eating and dangerous. Piranha are omnivores so are happy feeding on vegetable matter but many feed on other fish and small animals. In fact, legend has it that large Piranha packs have been known to devour an entire horse in minutes!
In the wild there's always a pecking order with a leader of the pack, when it comes to a school of Piranha. If one steps out of line the leader will discipline the wayward fish, sometimes in a fight to the death, and others may join in the attack. If the attacked fish dies the other Piranha may eat them. If it survives it has the ability to recover and repair very quickly.
Names: Striped Leporinus (Leporinus fasciatus).
Habitats: Tropical freshwater, native to rivers and flooded forests of South America.
Feed: Diet comprises of vegetative matter as well as other fish, worms, and crustaceans.
Special Features: Has a habit of sitting stationary in mid-water with its head down at a 30 degree angle.
The Striped Leporinus has eight to twelve vertical bands on its body and there is some variation in their colouration, with a bright yellow or beige body and transparent fins.
The Striped Leporinus with its elongated shape is unique in that it has a habit of sitting stationary in mid-water with its head down at a 30 degree angle. At this angle the fish is well camouflaged in amongst the roots of trees that line the rivers.
Names: Walrus Catfish (Synodontis spp.).
Size: Up to 50cm.
Feed: Small fish, crustaceans and other aquatic life.
Special Features: Can spend a large portion of the day swimming upside down.
Many of the species are nocturnal, usually hiding by day under logs, tree roots, and in crevices, becoming more active in the dim twilight hours. The Walrus Catfish can spend more time upside down that the right way up!