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Monday, November 26, 2007

Angelfish

Emperor Angelfish



The emperor angelfish, Pomacanthus imperator, is a species of marine angelfish. It is a reef-associated fish, native to the Indian and Pacific Oceans, from the Red Sea to Hawaii and the Austral Islands.



Juveniles are dark blue with electric blue and white rings; adults have yellow and blue stripes, with black around the eyes. It takes about four years for an emperor angelfish to acquire its adult colouring. They grow to 40 cm in length. Juvenile to adult transition may not fully occur in an aquarium.





Royal Angelfish



The royal angelfish, Pygoplites diacanthus, is a species of marine angelfish of the family Pomacanthidae, the only member of the genus Pygoplites. It is found in tropical Indo-Pacific oceans from Red Sea and East Africa to the Tuamoto Islands, north to Ryukyu and Ogasawara islands, south to the Great Barrier Reef and New Caledonia, at depths down to 48 m. Its length is up to 25 cm.

The royal angelfish occurs in coral-rich areas of lagoon and seaward reefs, often found in the vicinity of caves. It feeds on sponges and tunicates. It is solitary or in pairs, or in groups.

Coloration of the royal angelfish is sides with alternating dark-edged bluish white and orange stripes which narrow and angle backward in dorsal fin, the posterior portion of the dorsal fin black with close-set blue dots, the posterior portion of anal fin with alternating yellow and blue bands running parallel to body contour, and the caudal fin yellow. Juveniles have a large ocellated dark spot on the basal portion of the soft dorsal fin.

Although it is frequently exported through the aquarium trade it rarely survives in the aquarium.



Usually specimens abused during shipment, more likely caught by drugging, will refuse to eat anything, including live fare.

However, given the right environment, specifically with smaller and docile tankmates like gobies and dwarf angels, it will start feeding within days when fed brine shrimp, brine shrimp plus flakes, and further progessing to regular frozen foods and a certain brand of cichlid pellets which this species seem to crave.

With a hostile environment with fellow large angels, puffers, and triggers, and certain clowns, it will almost certainly fail to acclimate and slowly die of starvation due to its shyness to start feeding.

Survivability of feeding specimens seem to equal to the other Pomacanthids.

Fresh water dips may be required to rid newly arrived specimens of flukes and ick which this species is especially prone to.

The prior myth that only yellow-bellied variations from Sri Lanka and the Red Sea will survive points to the fact that species from the Philippines and Indonesia are often abused when collected.

King Angelfish




Thursday, November 22, 2007

Swell Shark



The swellshark, Cephaloscyllium ventriosum, is a catshark of the family Scyliorhinidae found in the subtropical eastern Pacific Ocean between latitudes 40° N and 37° S, from the surface to 460 m. It grows to about 1 m in length, and can expand its body by taking in air or water to make it appear larger to predators.

The swellshark is found on the continental shelves and upper slopes from inshore to deeper waters, preferring rocky, algal-covered areas of kelp beds. It is nocturnal and feeds on bony fishes, alive and dead, and probably crustaceans. Reproduction is oviparous. Swellsharks can live in aquaria for several years and females can lay eggs in captivity. In their natural state they can occur in aggregations while resting, sometimes piled one on top of the other. Sometimes they are caught by sport divers but they are not used.

Wednesday, November 21, 2007

Scalloped Hammerhead



The scalloped hammerhead, Sphyrna lewini, is a hammerhead shark of the family Sphyrnidae. Originally Zygaena lewini, it was later moved to its current name. The Greek word sphyrna translates into "hammer" in English, referring to the shape of this shark's head.

This shark is also known as the bronze, kidney-headed or southern hammerhead. It primarily lives in warm temperate and tropical coastal waters all around the globe between latitudes 46° N and 36° S, down to a depth of 300 m. It is the most common of all hammerheads.



The most distinguishing characteristic of this shark, as in all hammerheads, is the 'hammer' on its head. The shark's eyes and nostrils are at the tips of the extensions. The maximum length of the scalloped hammerhead is 4.3 m and the maximum weight 150 kg.

This shark is often seen during the day in big schools, sometimes numbering hundreds. They are considered dangerous but are normally not aggressive towards humans, in fact most incidents with humans are probably defensive after the shark was surprised or frightened.

This shark feeds primarily on fish such as sardines, mackerel and herring, and occasionally on cephalopods such as squid and octopus. Larger specimens may also feed on smaller species of shark such as the blacktip reef shark, Carcharhinus melanopterus.

Anemonefish

Clark's Anemonefish

Clark's anemonefish or the Yellowtail clownfish (Amphiprion clarkii) is a widely distributed clownfish. It is found in tropical waters, in lagoons and on outer reef slopes, from the Persian Gulf to Western Australia and throughout the Indian Ocean and Pacific Ocean as far as Melanesia and Micronesia, and as far north as Taiwan, southern Japan and the Ryukyu Islands.

Clark's Anemonefish is a spectacularly colourful fish, with vivid black, white and yellow stripes, though the exact pattern shows considerable geographical variation. There are normally two white bands, one behind the eye and one above the anus. The tail fin may be white or yellow, but is always lighter than rest of the body.

Clarke's Anemonefish are a popular aquarium species. They are omnivorous, and in the aquarium will readily eat brine shrimp. They will regularly host in many sea anemones in the home aquarium.

Barrier Reef Anemonefish

The Barrier Reef Anemonefish, Amphiprion akindynos, is an anemonefish of the family Pomacentridae. It is native to reefs and marine lagoons of the Western Pacific.

Adults are an orange-brown color with two white bars with black edging encircling the body. The first bar is located on the head behind the eyes and may be thin and broken. The second bar is on the body below the dorsal fin. The caudal peduncle and caudal fin are white. Juveniles are normally brown with three white stripes. In sub-adults the colouring changes to a dull yellow with two white stripes. They have 10 to 11 dorsal spines and 2 anal spines. They reach a maximum length of 9 cm (3½ in) and weigh on average 27.50 g (0.97 oz).





Saturday, November 17, 2007

Butterfly Fish



The butterflyfish are a group of conspicuous tropical marine fish of the family Chaetodontidae. Found mostly on the reefs of the Atlantic, Indian and Pacific Oceans, butterflyfish are fairly small, most from 12 to 22 cm in length. The largest species, the lined butterflyfish, Chaetodon lineolatus, grows to 30 cm. There are approximately 127 species in eleven genera. They should not be confused with the freshwater butterflyfish of the family Pantodontidae.



Butterflyfish are named for their brightly coloured and strikingly patterned bodies in shades of black, white, blue, red, orange and yellow (though some species are dull in colour). Many have eyespots on their flanks and dark bands across their eyes, not unlike the patterns seen on butterfly wings. Their deep, laterally compressed bodies are easily noticed through the profusion of reef life, leading most to believe the conspicuous coloration of butterflyfish is intended for interspecies communication. Butterflyfish have uninterrupted dorsal fins with tail fins that may be rounded or truncated, but are never forked.



The family name Chaetodontidae derives from the Greek words chaite meaning "hair" and odontos meaning "tooth." This is an allusion to the rows of brush-like teeth found in their small, protrusile mouths. Butterflyfish closely resemble the angelfish of the family Pomacanthidae but are distinguished from the latter by their lack of preopercle spines (part of the gill covers).



Their coloration also makes butterflyfish popular in the aquaria hobby. However, most species feed on coral polyps (corallivores) and sea anemones; this poses a problem in most reef tanks where a delicate balance is to be maintained. Species kept in the hobby are therefore the few generalists and specialist zooplankton feeders.



Generally diurnal and frequenting shallow waters of less than 18 m (some species found to 180 m), butterflyfish stick to particular home ranges. The corallivores are especially territorial, forming mated pairs and staking claim to their own head of coral. Contrastingly, the zooplankton feeders will form large conspecific groups. By night butterflyfish hide amongst the crevices of the reef and exhibit markedly different coloration than they do by day.



Butterflyfish are pelagic spawners; that is, they release many buoyant eggs into the water which then become part of the plankton, floating with the currents until hatching. The fry go through what is known as a tholichthys stage, wherein the body of the postlarval fish is covered in large bony plates extending from the head. This curious armoured stage is seen in only one other family of fish; the Scatophagidae (scats). The fish lose their bony plates as they mature.