September 23, 2008

Indonesian shortfin eel

Anguilla bicolor bicolor

Anguillidae (Freshwater eels)
Anguilliformes (eels and morays)
Class: Actinopterygii (ray-finned fishes)
FishBase name: Indonesian shortfin eel
Max. size: 120 cm TL (male/unsexed; Ref. 48660); max. reported age: 20 years
Environment: demersal; catadromous (Ref. 51243); freshwater; brackish; marine

Biology: Migratory species which breeds in the ocean (Ref. 52331). Lives in fresh water areas as an adult, in estuaries and seas as young (Ref. 12693). Descends to the sea to spawn. Inhabits freshwater streams and pools, preferring marshy habitats (Ref. 41236). Found in rivers and creeks, commonly over rock bottoms and in deeper pools. Seldom occurs in large rivers (Ref. 6028). Restricted to lowland (coastal) reaches of river systems (Ref. 7248). Feeds on small fishes, crustaceans and mollusks. Reported to breed east of Madagascar; the south equatorial current probably carries the eel larvae and elvers towards the east coast of Africa where local coastal currents guide the elvers to suitable rivers which they invade and they stay there until sexually mature, when they return to their breeding grounds (Ref. 13337). Caught with various types of nets. Sometimes used in the aquarium trade (Ref. 6028).
Red List Status: Not Evaluated (Ref. 57073)
Dangerous: harmless

Data i take from

The Indonesian shortfin eel, Anguilla bicolor bicolor, is a subspecies of eel in the genus Anguilla of the family Anguillidae. It is found throughout the tropical coastal regions of the Indian ocean and western Pacific.

Showing the typical habits, diet and characteristics of the genus, this species grows to 1.2 m and can live for up to 20 years. Dorsal fin soft rays number 240–250, anal fin soft rays 200-220, Vertebrae between 105 and 109 in number. This fish is lighter underneath, being olive/blue-brown on top. It is easily confused with the Pacific shortfin eel, Anguilla obscura.

September 22, 2008

Snake Head or "Ikan Gabus , Betutu, Ikan malas"

Common Snakehead

The Common Snakehead or Aruan is the most easily encountered of all Channa species. It is considered good eating and has medicinal value as a soup tonic; it is easily found in many Southeast Asian markets.

The species inhabits a variety of waterways including ponds, lakes, streams and drains. The dorsal side is brown in colour, the flanks have faint, slightly oblique bands, and the belly is white. Juveniles are more orange in colour. As with the Giant Snakehead Channa micropeltes, the juvenile fish are raised in a well protected underwater nest.

The species ranges throughout the Indian Subcontinent and Southeast Asia and has been introduced into many waterways.

Channidae is a family of freshwater fish commonly known as snakeheads, and is native to Africa and Asia. There are two extant genera, Channa in Asia, and Parachanna in Africa, consisting of 30-35 species. These predatory fishes are distinguished by a long dorsal fin, small head with large head scales on top, large mouth and teeth. They have a physiological need to breathe atmospheric air, which they do with a suprabranchial organ: a primitive form of a labyrinth organ.

They are considered valuable food fish. Larger species like Channa striata, Channa maculata or Parachanna obscura are farmed in aquaculture. Snakeheads feed on plankton, aquatic insects, and mollusks when small. When adult, they mostly feed on other fish like carp, or frogs. In rare cases, small mammals such as rats are taken. The size of the snakehead species differs greatly. "Dwarf snakeheads" like Channa gachua grow to 10 inches (25 cm). Most snakeheads grow up to 2 or 3 ft. (60–100 cm). Only two species (Channa marulius and Channa micropeltes) can reach a length of more than 1 meter and a weight of more than 6 kg.

It is illegal to keep snakeheads as pets in thirteen states of the USA and other countries as they have become an invasive species due to irresponsible owners releasing them into the wild when they could/would no longer take care of them. If in an enclosed area they will try anything to escape. If in an aquarium they will charge at full force and tend to knock over the aquarium or shatter the glass.Channidae is also known as the the Northern Snakehead, or Channa Argus, and is native to Asia. There are 29 known Snakehead varieties.

The National Geographic Channel reported:

A Northern Snakehead reaches sexual maturity by age 2 or 3. Each spawning-age female can release up to 15,000 eggs at once. Snakeheads can mate as often as five times a year. This means in just two years, a single female can release up to 150,000 eggs...

'They can travel across land and live out of water for up to three days,' [says U.S. Secretary of the Interior Gale Norton].

[Snakeheads can breathe air unlike other fish as they] use a primitive lung above their gills... [or] 'air chambers'.

Out of the water Snakeheads rhythmically move their fins and muscular bodies back and forth: the fish equivalent of walking... It's a resourceful adaptation. [In their native Asia they must survive both wet and dry weather cycles like monsoons and droughts.]

When the Snakehead eats it is a thrust predator. It will eat its prey all at once, striking and ingesting it whole.

The Giant Snakehead, or Channa micropeltes, is native throughout Asia, and is the most aggressive Snakehead. They can grow to over 1.5 metres long. Adult Snakeheads force their hatchlings to breathe air by pushing them to the surface.

From 2002 to 2003, one Los Angeles supermarket was found to have sold approximately 25,000 dollars worth of illegal live Snakeheads which caused breakouts in local eco systems.

It has had recent sightings in Lincolnshire (UK) (which proved to be hoax) and in the U.S. National Geographic referred to it as "Fishzilla".

Prehistory and evolution

Channidae are well-represented in the fossil record and known from numerous specimens. Research indicates that snakeheads likely originated in the south Himalayan region (modern-day Pakistan) at least 50 million years ago, during the Early Eocene epoch. By 17 Ma, during the Early Miocene, Channidae had spread into western and central Eurasia, and by 8 Ma, during the late Tortonian, they could be found throughout Africa and East Asia. As Channidae are adapted to climates of high precipitation with mean temperatures of 20 °C (68 °F), their migrations into Europe and Asia correspond to the development of the Intertropical Convergence Zone, which increased air humidity, and the intensification of the East Asian monsoon, respectively. Both weather patterns emerged due to greater vertical growth of the Alps, Pyrenees, and Himalayas, which affected Eurasian climactic patterns.

Ecological concerns

Snakeheads can become invasive species and cause ecological damage because they are top-level predators, meaning that they have no natural enemies outside of their native environment. Not only can they breathe atmospheric air, but they can also survive on land for up to four days, provided they are wet, and are known to migrate on wet land to other bodies of water by wriggling with their body and fins.

Snakeheads became a national news topic in the US because of the appearance of northern snakeheads spawning in a Maryland pond in 2002.Northern snakeheads became permanently established in the Potomac River around 2004, and possibly established in Florida. Apparently non-established specimens have been found in Flushing Meadows-Corona Park, New York, as well as Wawayanda, New York, two ponds outside Philadelphia, Pennsylvania a pond in Massachusetts, and reservoirs in California and North Carolina.

They are prohibited in several other countries,like Australia, because their introduction to new ecosystems may displace indigenous species. Humans have been introducing snakeheads to non-indigenous waters for over 100 years. In parts of Asia and Africa, the snakehead is considered a valuable food fish and is produced in aquacultures. Due to this fact it was introduced either on purpose (fisheries motivation) or by ignorance (as was the case in Crofton).

Some examples of the introduction of snakeheads to non-indigeneous waters include:

  • Channa maculata was introduced to Madagascar and to Hawaii around the end of the 19th century. It can still be found there today.
  • Channa striata was introduced to islands east of the Wallace line by governmental programs in the later half of the 20th century. In Fiji, the introduction failed.
  • Channa asiatica, which is native to southern China, was introduced to Taiwan and to southern Japan. In this case the origin and reason of the introduction is unknown, but most probably due to human intervention.
  • Channa argus, which is native to northern China (Amur River), was introduced to Central Asia (Kazakhstan, Turkmenistan, Uzbekistan). It was introduced to Japan about 100 years ago due to fisheries motivations. Its introduction to Czechoslovakia by the government in the 1960s failed due to cold winters.

A comprehensive work on the dangers of the introduction of snakeheads to non-indigeneous waters is that of Prof. W. Courtenay.

September 13, 2008

Choose Fish for a Freshwater Aquarium

Choosing the right inhabitants for your aquarium requires a bit more thought than simply matching their colors to your couch. Follow these simple steps to fish bliss.

*. Determine the number of fish you can house by the size of your tank. A general rule of thumb is to allow 2 inches of fish per gallon of water.

*. Buy your fish from a reputable dealer who will back up his product. You want clean fish that won't get each other sick. A good sign that the seller knows what he's talking about is his show tank. Do the fish seem happy? Is it the way you imagine your tank looking when it's complete? If you see dead things floating in the tanks, look elsewhere.

*. Read about the fish you want. Some have particular needs, whether temperature, chemical, dietary, or compatibility-related.

*. Get school fish. Compatibility problems are minimal and it will be easy to see if any of the fish are behaving oddly (indicating illness). Try neons or cardinal tetras, Corydoras catfish, any of the small barbs, rasboras, loaches, or pearl and zebra danios.

*. Resist the urge to get one of everything you like, particularly with school fish.

*. Try a bristle-nose or clown plecostomus, or a pair of otocinclus catfish to help control the algae.

*. Raise killifish, which are excellent for a beginning aquarium, but difficult to find.

*. Ask your fish dealer about compatibility with other fish in your tank. Be careful of cichlids ' some grow quite large. Angelfish require tanks larger than 10 gallons. Stay away from Oscars, which tend to eat the other fish and are particularly messy.

*. Avoid the urge to impress people with a piranha. This shy fish has the unfortunate honor of eating many of those unhealthy goldfish. This is not only expensive, but unless you want to quarantine every feeder fish you buy, you're likely to have issues with disease and parasites. They are school fish but need to be well-fed or they will eat each other.

*. Think about Bala sharks, which are cool-looking non-sharks. They grow to more than 12 inches, however, so unless you're ready to accommodate that much fish, it's best to leave these alone.

*. Avoid catfish in general. They are nasty predators and tend to grow. And grow. And grow '

Quarantine every new fish before you add it to your tank.

When you bring your new fish home, wrap the plastic bag that it's in in something opaque. The easiest way is to put it in a paper bag.

Be sure to introduce the fish to its new environment slowly. Equalize the water temperature by floating the bag in the tank. Add tank water periodically to the bag water.

Keep the lighting minimal for the first few days the fish is in its new home.

Be sure there are plenty of hiding places for your new fish.

Don't add more than four fish at a time; you don't want to cause a chemical imbalance in the tank.

Stay away from goldfish, which are not true tropical fish and require cooler temperatures than many other species. They also tend to have many health problems.

Knife fish are suspicious additions to your new tank. Look to this nocturnal predator when your other fish begin to disappear.

Tips from eHow Users:
Research your fish before you buy by Shelly H.
I am a beginner only 3 years in the hobby. I've had some expensive and disappointing experiences. Always research your fish. "Clown Knives" are a beautiful fish and seem very docile, but when the lights are out, "fish beware." They are nocturnal feeders.

This article i grab from because i think is goods, so i catch this file.
credit to . Thanks u.