Saturday, April 9, 2011

Gouramy Fish

All Gourami species are tropical fish belonging to the Labyrinth family, and they live exclusively in fresh water. The Labyrinth family include several other notable members, such as the Climbing Perch and the Betta / Fighting Fish. What all Labyrinth species have in common is the presence of labyrinth-shaped breathing organs connected to each gill chamber. This adaptation makes Labyrinth fish, such as the Gouramis, very suitable for a life in low oxygen waters, since the organs make it possible for the fish to absorb oxygen directly from the air.  All Gourami species originate from Africa and Asia, and there are approximately 12 different Gourami species frequently kept in aquariums today. Many of the Gourami species can be found in several different colour variations.
The Gourami species named Osphronemus goramy is considered the “true Gourami”. It originates from Indonesia, but is today found wild in Chinese and South Asian waters as well. It has been deliberately introduced by man and is considered a delicates. Osphronemus goramy is sometimes called Giant Gourami, since it grows very fast and can exceed 60 centimetres / 2 feet in length. If you wish to keep an Osphronemus goramy you must therefore provide it with a very large aquarium, and also keep in mind that it can live for 25 years or longer in captivity. It comes as no surprise that other Gourami species than the “True Gourami” are more popular as house pets today.
Helostoma temmincki, the Kissing Gourami, is the most popular Gourami species among aquarists. It seldom grows bigger than 25 centimetres / 10 inches. The so called Talking Gourami, Trichopsis vittatus, is an even better choice if you have a smaller aquarium since it will stay around 5 centimetres / 2 inches. The Talking Gourami is also called the Croaking Gourami, since the male fish produces a croaking sound when it surfaces during the night to breed oxygen from the air. If you want a somewhat larger Gourami in your aquarium, the Moonlight Gourami (Trichogaster microlepis ) is a good option. It is comparatively easy to care for and typically reaches a length of 15 centimetres / 6 inches. The Moonlight Gourami features threadlike ventral fins and derives its name from its silvery-blue colouration.
A majority of the Gourami species appreciates the same type of living condition, since there do exists a few differences between the species regarding preferred water temperature, pH-value, diet requirements etcetera it is always recommended to do some reading regarding your particular Gourami species as well. Generally speaking, Gouramis will do well in water temperatures around 24 – 26 degrees C (74 – 79 degrees F). When it comes to pH-values, neutral or slightly acidic water will be best for the Gourami. Gouramis also prefer to be kept in relatively soft water. The aquarium where your keep your Gourami should be well planted, preferably with sturdy plants such as Java Fern, Vallisneria or Cryptocoryne plants. Cover the bottom of the aquarium with a neutrally coloured fine or medium sized substrate.
Gouramis must be kept on a varied to get all necessary nutrients. They are usually happy eaters in the aquarium and will accept most food types. They are quite sturdy and will often survive even on a less than optimal diet, but such a diet will make them more prone to illness and they will not look their best. Dry or frozen prepared foods are a good base that can be supplemented with live foods. Fresh vegetables are also a good addition, e.g. lettuce and peas.
Gouramis love Brine Shrimp and all kinds of worms (Glass worms, Black worms etc). The Gourami is a popular fish in community aquariums since it is relatively peaceful and gets along fine with most other fish. The best companions for a Gourami are other peaceful species of approximately the same size as the Gourami. Other Labyrinth and dwarf cichlids are frequently kept with Gourami. You can also keep several Gouramis in the same aquarium, as long as the aquarium is big enough for them to claim their own territories. Natural barriers in the aquarium, such as plants, will reduce the amount of fighting between Gouramis since they can stay out of each others sight.

Tuesday, March 8, 2011

Piranha


A piranha or piraña is a member of family Characidae in order Characiformes, an omnivorous freshwater fish that inhabits South American rivers. In Venezuela, they are called caribes. They are known for their sharp teeth and a voracious appetite for meat. Piranhas belong to the subfamily Serrasalminae, which also includes closely related omnivorous fish such as pacus. Traditionally, only the four genera Pristobrycon, Pygocentrus, Pygopristis and Serrasalmus are considered to be true piranhas, due to their specialized teeth. However, a recent analysis showed that, if the piranha group is to be monophyletic, it should be restricted to Serrasalmus, Pygocentrus and part of Pristobrycon, or expanded to include these taxa plus Pygopristis, Catoprion, and Pristobrycon striolatus.
Pygopristis was found to be more closely related to Catoprion than the other three piranha genera. The total number of piranha species is unknown and contested, and new species continue to be described. Estimates range from fewer than 30 to more than 60. Piranhas are found in the Amazon basin, in the Orinoco, in rivers of the Guyanas, in the Paraguay-Paraná, and the São Francisco River systems. Some species of piranha have broad geographic ranges, occurring in more than one of the major basins mentioned above, whereas others appear to have more limited distributions.
Aquarium piranhas have been introduced into parts of the United States, with specimens occasionally found in the Potomac River, Lake of the Ozarks in Missouri and even as far north as Lake Winnebago in Wisconsin, although they typically do not survive cold winters. Piranhas have also been discovered in the Kaptai Lake in southeast Bangladesh. Research is being carried out to establish how piranhas have moved to such distant corners of the world from their original habitat. Some rogue exotic fish traders are thought to have released them in the lake to avoid being caught by antipoaching forces. Piranhas were also spotted in the Lijiang River in China. Piranhas are normally about 14 to 26 cm long (5.5 to 10.25 inches), although some specimens have been reported to be up to 43 cm (17.0 inches) in length. Serrasalmus, Pristobrycon, Pygocentrus and Pygopristis are most easily recognized by their unique dentition.
All piranhas have a single row of sharp teeth in both jaws; the teeth are tightly packed and interlocking (via small cusps) and are used for rapid puncture and shearing. Individual teeth are typically broadly triangular, pointed and blade-like (flat in profile). There is minor variation in the number of cusps; in most species, the teeth are tricuspid with a larger middle cusp which makes the individual teeth appear markedly triangular. The exception is Pygopristis, which has pentacuspid teeth and a middle cusp usually only slightly larger than the other cusps. In the scale-eating Catoprion, the shape of their teeth is markedly different and the premaxillary teeth are in two rows, as in most other serrasalmines. Piranhas are important ecological components of their native environments.
Although largely restricted to lowland drainages, these fish are widespread and inhabit diverse habitats within both lotic and lentic environments. Some piranha species are abundant locally, and multiple species often occur together. As both predators and scavengers, piranhas influence the local distribution and composition of fish assemblages.  Certain piranha species consume large quantities of seeds, but unlike the related Colossoma and Piaractus, herbivorous piranhas thoroughly masticate and entirely devour all seeds eaten and consequently do not function as dispersers. Piranha have a reputation as ferocious predators that hunt their prey in schools.
 Recent research, however, which "started off with the premise that they school as a means of cooperative hunting", discovered that they are timid fish that schooled for protection from their own predators, such as cormorants, caimans, and dolphins. Piranhas are "basically like regular fish with large teeth". Research on the species Serrasalmus aff. brandtii and Pygocentrus nattereri in Viana Lake, which is formed during the wet season when the Rio Pindare (a tributary of the Rio Mearim) floods, has shown that these species eat vegetable matter at some stages in their life; they are not strictly carnivorous fish.Piranha teeth are often used to make tools and weapons by the indigenous population. Piranhas are also popular as food, although if an individual piranha is caught on a hook or line, it may be attacked by other (free) piranhas.[citation needed] Piranhas are commonly consumed by subsistence fishermen, and often sold for food in local markets. In recent decades, dried specimens have been marketed as tourist souvenirs. Piranhas occasionally bite and sometimes injure bathers and swimmers. A piranha bite is considered more an act of carelessness than that of misfortune, but piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.

Wednesday, February 2, 2011

Cat Fish


Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa. There are armour-plated types and also naked types, neither having scales. Despite their name, not all catfish have prominent barbels; members of the Siluriformes order are defined by features of the skull and swimbladder. Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly the genus Corydoras, are important in the aquarium hobby.
Catfish are nocturnal.Extant catfish species live inland or in coastal waters of every continent except Antarctica. Catfish have inhabited all continents at one time or another.Catfish are most diverse in tropical South America, Africa, and Asia.More than half of all catfish species live in the Americas. They are the only ostariophysans that have entered freshwater habitats in Madagascar, Australia, and New Guinea.
They are found in freshwater environments, though most inhabit shallow, running water. Representatives of at least eight families are hypogean (live underground) with three families that are also troglobitic (inhabiting caves). One such species is Phreatobius cisternarum, known to live underground in phreatic habitats. Numerous species from the families Ariidae and Plotosidae, and a few species from among the Aspredinidae and Bagridae, are found in salt water.
In the United States, catfish species may be known by a variety of slang names, just as mud cat, polliwogs, or chuckleheads. These nicknames are not standardized, so one area may call a Bullhead catfish by the nickname chucklehead, while in another state or region, that nickname refers to the Blue catfish.Most catfish are bottom feeders. In general, they are negatively buoyant, which means that they will usually sink rather than float due to a reduced gas bladder and a heavy, bony head.
Catfish have a variety of body shapes, though most have a cylindrical body with a flattened ventrum to allow for benthic feeding. A flattened head allows for digging through the substrate as well as perhaps serving as a hydrofoil. Most have a mouth that can expand to a large size and contains no incisiform teeth; catfish generally feed through suction or gulping rather than biting and cutting prey. However, some families, notably Loricariidae and Astroblepidae, have a suckermouth that allows them to fasten themselves to objects in fast-moving water. Catfish also have a maxilla reduced to a support for barbells this means that they are unable to protrude their mouths as other fish such as carp. Catfish may have up to four pairs of barbels: nasal, maxillary (on each side of mouth), and two pairs of chin barbels, even though pairs of barbels may be absent depending on the species.
Catfish also have chemoreceptors across their entire bodies, which means they "taste" anything they touch and "smell" any chemicals in the water. "In catfish, gustation plays a primary role in the orientation and location of food". Because their barbels and chemoreception are more important in detecting food, the eyes on catfish are generally small. Like other ostariophysans, they are characterized by the presence of a Weberian apparatus.
Their well-developed Weberian apparatus and reduced gas bladder allow for improved hearing as well as sound production.Catfish have no scales; their bodies are often naked. In some species, the mucus-covered skin is used in cutaneous respiration, where the fish breathes through its skin. In some catfish, the skin is covered in bony plates called scutes; some form of body armor appears in various ways within the order.
In loricarioids and in the Asian genus Sisor, the armor is primarily made up of one or more rows of free dermal plates. Similar plates are found in large specimens of Lithodoras. These plates may be supported by vertebral processes, as in scoloplacids and in Sisor, but the processes never fuse to the plates or form any external armor. By contrast, in the subfamily Doumeinae (family Amphiliidae) and in hoplomyzontines (Aspredinidae), the armor is formed solely by expanded vertebral processes that form plates. Finally, the lateral armor of doradids, Sisor, and hoplomyzontines consists of hypertrophied lateral line ossicles with dorsal and ventral lamina


Thursday, January 13, 2011

Giant snakehead

 
The giant snakehead or giant mudfish (Channa micropeltes) is the largest in the family Channidae, capable of growing to over 1 meter in length (3.3 feet) and a weight of over 20 kilograms (44 pounds). It is widely distributed in the freshwater of South East Asia and some regions of India. Other names include red snakehead, redline snakehead, Malabar snakehead, and Ikan toman (where ikan is "fish" in both Indonesian and Malay). The giant snakehead is known in Thai language as Pla Chado. The young of the giant snakehead are red in color, with orange and black lateral stripes appearing after about two months. As the giant snakehead matures, they lose their stripes and redness, and instead develop a bluish black and white pattern on their upper body.
Juveniles sold in the aquarium fish trade are commonly called "red snakeheads". They can get up to 6 feet long and up to 66 pounds. Giant Snakeheads are the most aggressive species of the 30 species of Snakeheads.The species has the ability to crawl onto land and breathe air, although they are only able to do this in muddy or swampy areas, hence the nickname "mudfish". Its ability to breathe air using a primitive lung located just behind the gills allows it to survive in stagnant water where oxygen levels are low, by coming to the surface and taking a small gulp of air. It also enables the snakehead to travel short distances on land, although it is unable to hunt while on land, as it cannot support itself at all with its small fins in comparison to its large body.
In Malaysia and Singapore, known locally as the toman, while in Indonesia are called gabus or haruan (not to be confused with another species of smaller snakehead known as the common snakehead also called haruan), are cultured in fish ponds and reservoirs as game fish because they put up a strong fight when hooked. The giant snakehead is also a good food fish, and is often served in Chinese restaurants. In Thailand this fish is prepared in a variety of ways, especially barbecued, being a common food item offered by street vendors. In various Asian cultures it is believed that eating this fish will help in healing of the body, for example, after surgery or severe cuts and scrapes.
The giant snakehead, normally called red or redline snakeheads are a popular fish to be sold in the pet trade. They are commonly sold as juveniles as pets. Some are even sold as feeders to be fed to larger carnivorous fish. Generally peaceful while young, they grow into voracious predators that will chase and eat anything that fits in their mouth. Due to this they are mostly called "freshwater great whites". However, they can successfully be housed with silver arowanas, clown knife fishes, oscars, and other fish from same size group.
The giant snakehead is found in Vietnam, Indonesia, Laos, Thailand, Malaysia, India, and possibly Burma. It has an oddly disjunctive distribution, inhabiting both Southeast Asia and southwest India, about 2500 km apart. It is theorized that the Indian population may be from an early human introduction, prior to the 19th century. In India it is found in southern Tamil Nadu and Kerala especially in Pechipparai, Chittar I & II, Neyyar and Temnalai Reservoirs.
Ebanasar (1995) reported its distribution and Biology from these reservoirs.Ebanasar (1995) has also conducted series of experiments on the biology, physiology and culture of this fish. It is reported that this fish is highly suitable for cage culture and culture in ponds in combination with tilapia. It is found to be an effective tool in controlling the overpopulation of tilapia and thus checks stunted growth of tilapia. There have been reports of the giant snakehead in already six of the US states including Wisconsin, Maryland, and parts of Virginia.