AMAZON CATFISH - Piraiba

In the Amazon River, there are legends of goliath catfish that grow to over 10 feet long and reach nearly 600 pounds. These giants are the catfish that belong to the Brachyplatystoma genus. This genus has 7 of the largest fish in the world, including B. filamentosum. This fish is so large that locals call the juvenile fish (those weighing under 200 pounds) filhote. Once they reach 200 pounds, locals call them Piraiba. The Piraiba is the largest catfish in this genus, and is notorious for its voracious eating and solitary lifestyle habits.

When they’re juveniles, Piraiba are light to dark grey with small spots on their dorsal and lateral sides. As they get older, Piraiba turn dark grey on the top and light grey on the bottom. This coloration aids in camouflaging their massive bodies as they hunt for food 100-130 feet below the surface of the Amazon River.

Piraiba have an appetite to match their massive bodies. Fishermen who’ve caught these massive giants have found small monkeys, birds, cats and even other catfish in the stomachs of these giants. While they don’t hunt for monkeys or birds, Piraibas have no problem scavenging on already deceased animals that have fallen into the Amazon. Some legends even claim that humans have been found in the stomachs of these enormous fish.

Piraibas not only play an important role as scavenger in the Amazon. They also play an important role as food for locals. Fishermen and anglers who hunt these large fish will drop many lines into the Amazon, weighted down by 2-5 pound bait and rocks. Once the line begins to move, experienced fishermen draw the fish into shallow water. At that point, the fishermen have no option but to jump into the water and literally wrestle the Piraibas to ground. For

inexperienced fishermen this can be a very dangerous sport to learn—the Piraibas are so powerful that they can drown and even drag the wrestling fishermen to the bottom of the Amazon. A successful catch is well worth it though, as a single Piraiba can contain hundreds of pounds of food for locals and export.

Like other catfish, the Piraiba are active at night between midnight and around 6 a.m. Piraiba catfish look for food as deep as 130 feet under the surface of the Amazon River. They will scavenge and also hunt for smaller fish such as Peacock Bass and Piranha. Piraiba don’t worry about the slicing teeth of the Piranha, even though they inhabit the same waters where hundreds of Piranha school. These giants have extremely thick tough leathery skin that resists such attacks. By the time they are 4-5 feet in length, Piraibas can move freely in the deepest Amazon waters without fear of predators.

Piraibas remain solitary until they are ready to mate somewhere between 2-3 years old. When a male is ready to mate, he will find another female Piraiba and swim alongside her until she releases eggs. The male will inseminate hundreds of eggs, and then chase the female from the eggs. The male aerates the eggs and keeps the female away, while the female chases predators away from a distance. Within a week, the fry hatch and are fed by the male stirring up detritus on the Amazon floor. The female remains a guardian during this period.

The fry remain at the nest for up to several weeks, adventuring to find small invertebrates and ghost shrimp to eat. They grow fairly quickly, and by 6-8 months they begin to take on sexual distinction and become solitary. This is the most vulnerable period for the young Piraiba—they are mature enough to hunt on their own, but their size makes them very vulnerable to larger fish, giant otters and predatory birds. The Piraiba’s body does offer some protection against such predators that would eat them whole—a characteristic sharp collection of spines on their dorsal that deters predation.

With such a large potential size and healthy appetite, Piraibas are definitely not suitable for most aquarium owners. The best spot to keep a Piraiba is a large local aquarium that can support at least a 2000 gallon tank. These fish can get up to 400 pounds, and with this much body weight, this fish is one of the most expensive to feed and maintain.

Piraiba are one of the most impressive catfish in the world. They dominate the Amazon with their sheer size, and offer fishermen an exciting, challenging catch. They also play a crucial role in scavenging the bottom of the Amazon as the “clean-up crew” of the largest river system on Earth.

CATFISH - Clarias batrachus

There is a few varieties of Clarias batrachus, the normal coloured which is a slate grey to olive colouration with a white underbelly and an albino variation which unusual to most fish species, occurs in nature. The albino is of course white all over with red eye's. Another much prettier one is is the above image, piebald/pink, and has normal eye's.

It received its common name of the 'Walking Catfish' on its ability to walk overland from pond to pond when their original habitat dries up or after a heavy rainfall. They possess a much reduced air-bladder and their gills are stiffened to prevent their collapse when out of water and in a special part of the gill chamber are spongy arborecent (tree-like) organs growing from the upper ends of the gill arches. These and the skin surrounding them, are well supplied with blood vessels and operate efficiently in water lacking in oxygen or when the fish is out of water. They of course keep their gills closed when out of water and as long as their body is kept moist they can stay on land for a considerable length of time.

Clarias batrachus = Albino

Their distinguishing features are of course its long dorsal fin ( 62-77 rays) without a spine and its long anal fin (45-63 rays). Both these fins usually have a break before the small rounded caudal fin but sometimes in odd specimens the fins of the dorsal and anal fuse to the caudal. Its pectoral spines are very strong ( 1 spine 8-11 rays) especially the leading spine which of course helps its odd lifestyle of moving about on dry land. It possess 4 pair of barbels, one pair of nasal, one pair of maxillary and two pairs of mandibular barbels.

Clarias batrachus = Normal Variety

It is native to Southeastern Asia but was brought into the U.S. in the 1960's for fish farming and it was out of one of these farms in Florida in the mid 60's that the first escape occurred and the first catch of this fish was by an angler on the 15th March 1967.  The first escapees originated from wild stock which was exported from Thailand. It is a threat to the native fish populations in the Florida and Gulf of Mexico areas and the only enemy of this fish (apart from the anglers) is if there is a very cold winter and they can not survive the long cold spell.

As mentioned at the start of this factsheet, they are predators and very good escape artists as well so if you do fancy keeping them a tight lid is essential with large hiding places, a soft bottom ( sand or rounded gravel) and of course a large tank of 4ft or larger and outside filtration.

The male of this species is usually more colourful than the female with a dark spot on the rear of the dorsal fin, the female does not possess this. This of course relates to the normal variety and I'm not sure if this could be applied to the albino, but the larger girth of the female in breeding condition would set them apart.

Characteristics
Dorsal fin 62-77 rays without a spine. Anal fin 45-63 rays. Both these fins usually have a break before the small rounded caudal fin but sometimes in odd specimens the fins of the dorsal and anal fuse to the caudal. Pectoral;1 spine 8-11 rays. 4 pair of barbels, one pair of nasal, one pair of maxillary and two pairs of mandibular barbels.

Colour
There is a few varieties of Clarias batrachus, the normal coloured which is a slate grey to olive colouration with a white underbelly. Albino, white all over with red eye's. Another variety is piebald/pink and has normal eye's.

Compatibility

Very much a predator so would need to be kept alone or with its own kind as in a pair.

Breeding

It is reported that they engage in mass spawning migrations in late spring and early summer. Adhesive eggs are laid in a nest or in submerged vegetation and the males guard the eggs. There is a breeding report published in the German magazine DATZ (7/04, pages 12-15) by Wolfgang Ros.

Below is a short extract in English kindly supplied by Wolfgang from his article:

"At least in the breeding time of Clarias batrachus there seems to be a kind of pair connection. The mating altogether takes about 20 hours. Before both partners are digging a hollow, which has a diameter of approximately 12 inch. In some descriptions also the building of a nest is described. I cannot confirm that. There are some hundreds up to a thousand eggs. As soon as the female delivered all eggs, it avoids the mating hollow. This part is guarded only by the male, the female secures the place behind. The embryos slipped out after approximately 30-40 hours. After further two days both partners are no more protecting the spawn." You can access further articles on ScotCat of Clarias batrachus by Wolfgang below.

Final speech for the “Walking Catfish”, Clarias batrachus
Pair behaviour of the “Walking Catfish”, Clarias batrachus
Initiating reproduction with the Walking Catfish (Clarias batrachus)

Feeding
In its native habitat it is a scavenger and will eat smaller fish and are opportunist feeders and so will eat just about anything!. In the aquarium they are not fussy feeders but fish of some sort should be on the menu but does not necessary need to be live food.

Etymology
Clarias: Clear or shining.
batrachus: From ‘batrachus’, a frog; frog-like.

References
Baensch; Aquarium Atlas1.1989.
Ros, Wolfgang; DATZ (7/04, pages 12-15) http://wolfgang-ros.de.tt (home page)

Technorati Tags: Clarias batrachus (Linnaeus,1758)

CATFISH - Clarias gariepinus and Clarias anguillaris

Pond culture is not a traditional farming practice in most parts of Africa. Introduced after the Second World War there was an initial spectacular aquaculture development with about 300,000 ponds being operational, mainly rearing Tilapia spp., in about 20 African countries by the end of the fifties (Meschkat, 1967). Since then fish culture has not made much further progress and has in many cases even declined resulting in the abandonment of fish ponds by discouraged farmers. According to the authors this failure has been attributed to:

· The harvesting of too many small stunted tilapia from over populated ponds because of the use of poor husbandry techniques.· The dependency on subsidized extension services and fingerling distribution centres.
· Misjudgement of the motivation of the rural fish farmers by policy makers, and the creation of the myth that the rural farmer will willingly take up fish farming for food security or as a source of protein for their family. This is most likely not the case, the primary motivation of the rural fish farmer generally being income generation.
· Failure to apply adequate resources (which may be naturally limiting) such as water and feed.

By the end of the sixties, a reorientation to increase aquaculture production was proposed that included:

· A modification of the farming technique for Tilapia spp. in which seed production and on-growing to marketable-sized fish are separated and the introduction of monosex tilapia culture (Pruginin, 1967 and Shell, 1968).· Identification of new, more suitable species for aquaculture development (Lemasson and Bard, 1968).

It was soon recognized that the African catfish Clarias gariepinus (Burchell 1822) was one of the most suitable species for aquaculture in Africa (CTFT, 1972; Micha, 1973; Pham, 1975; Jocque, 1975; Kelleher and Vincke, 1976; Richter, 1979; Hogendoorn, 1979) and since the seventies it has been considered to hold great promise for fish farming in Africa; the African catfish having a high growth rate, being very resistant to handling and stress, and being very well appreciated in a wide number of African countries.

The development of a reliable method for the production of C. gariepinus fingerlings was one of the priorities of aquaculture research in Africa (Anonymous, 1987a). Hormone-induced reproduction of the African catfish using deoxycorticosterone acetate, human chorionic gonadotropin and common carp pituitaries has been carried out successfully (Hogendoorn and Wieme, 1976; Hogendoorn and Vismans, 1980; Micha, 1976; Kelleher and Vincke, 1976; El Bolock, 1976).

Hogendoorn (1980) and Hogendoorn and Vismans, (1980) successfully developed an intensive farming system for African catfish fingerling production based on the use of Artemia salina nauplii and a commercial trout starter as feed. However the existence of technically feasible farming methods and manuals (Viveen et al., 1985) did not guarantee a successful implementation, as the impact of local socio-economic and technical conditions are more often than not always under-estimated (Anonymous, 1987b). The introduction of intensive rearing methods in the Central African Republic and the Ivory Coast encountered numerous technical and economic problems (Janssen, 1985a, 1985b and 1985c; de Graaf, 1989).

The main problem encountered with fingerling production in ponds was the poor and erratic fish survival rate; production varying from 0 to 60 fingerlings/m²/cycle (Micha, 1973, 1976; Hogendoorn, 1979; Hogendoorn and Wieme, 1976; Kelleher and Vincke, 1976). It has been suggested that the lack of appropriate feed and the presence of predators are the more likely causes of this mortality. In the late eighties a simple and reliable method was developed in the Republic of the Congo for the nursing of C. gariepinus within protected ponds (de Graaf et al., 1995) and this study indicated that competition for feed and cannibalism were the major factors affecting the pond nursing of C. gariepinus. The methodology as developed in the Republic of the Congo is now being used in many other African countries and an instruction video on this technique; “Anou is raising catfish” was produced by the FAO project (UNDP/FAO/PRC/88/007, Phase II) in the Republic of the Congo and can be obtained from the Nefisco Foundation, Amsterdam, the Netherlands (see Annex I).

The last twenty years has seen considerable gains in our knowledge concerning the reproduction and rearing of C. gariepinus, and in particular through the activities of FAO projects in the Central African Republic, the Republic of the Congo and Kenya; Centre Technique Forestier Tropical (CTFT) projects in the Ivory Coast; research programmes of the Department of Technology and Fisheries Science of the Rhodes University, South Africa and through basic research programmes carried out by the Department of Aquaculture and Inland Fisheries of the Wageningen University in the Netherlands and other Universities and Institutes throughout the world.

In the present paper an attempt is made to compile and update available knowledge concerning the rearing of C. gariepinus with particular emphasis on African conditions.

A number of the illustrations used in this paper have been presented before in the publication of Viveen et al., (1985) and permission given to use the illustrations in the present handbook is gratefully acknowledged.

Although more than 100 different species of the Genus Clarias have been described in Africa, a recent systematic revision based on morphological, anatomical and biographical studies has been carried out by Teugels (1982a, 1982b, 1984), who recognized 32 valid species. The large African species which are of interest for aquaculture belong to the subgenus Clarias. In earlier systematic studies on the large African catfish species Boulenger (1911) as well as David (1935) recognized five species within this subgenus. Both authors used morphological criteria such as form of vomerine teeth, ratio of vomerine to premaxillary teeth band and the number of gill rakers. The five species were:

· Clarias anguillarus
· Clarias senegalensis
· Clarias lazera
· Clarias mossambicus
· Clarias gariepinus

Natural geographical distribution

Clarias gariepinus, which is generally considered to be one of the most important tropical catfish species for aquaculture, has an almost Pan-African distribution, ranging from the Nile to West Africa and from Algeria to Southern Africa. They also occur in Asia Minor (Israel, Syria and South of Turkey). By contrast, Clarias anguillaris has a more restricted distribution and is found in Mauritania, in most West African basins and in the Nile (Figure 2). In general C. gariepinus lives in most river basins sympatrically with C. anguillaris.