Nandus+Nebulosus

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 * //Nandus Nebulosus// (Sunda Leaf Fish) **

**Is it a leaf? Or a fish?** The Sunda Leaf Fish specializes in the art of mimicry. Not only does it resemble a dead leaf, it also behaves like one! This elusive fish is native to Singapore, so take a closer look the next time you see a bunch of dead leaves in the waters of our reservoirs and freshwater streams. Who knows, you might just spot a leaf fish!

**Names**
 __ Scientific: __ //Nandus nebulosus// Gray 1835  __ Common: __  English: Sunda leaf fish, Bornean leaf fish, Malayan leaf fish  Chinese: 枯叶鱼   Malay: Ikan Daun Kering  <span style="font-family: Verdana,Geneva,sans-serif;">__ Original description: __ //Beluda nebulosus// Gray 1835   <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="font-family: Verdana,Geneva,sans-serif;">__ Synonym: __ //Nandus borneensis// Steindachner 1901   <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="font-family: Verdana,Geneva,sans-serif;">__ Etymology: __The species epithet has its origins from the Latin adjective nebulosus, meaning cloudy. It may possibly refer to the 'cloudy', mottled brown coloration on its body.
 * ~ ===<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">Taxonomic Classification === ||
 * < <span style="font-family: Verdana,Geneva,sans-serif;">Kingdom ||< <span style="font-family: Verdana,Geneva,sans-serif;">Animalia ||
 * < <span style="font-family: Verdana,Geneva,sans-serif;">Phylum ||< <span style="font-family: Verdana,Geneva,sans-serif;">Chordata ||
 * < <span style="font-family: Verdana,Geneva,sans-serif;">Class ||< <span style="font-family: Verdana,Geneva,sans-serif;">Actinopterygii ||
 * < <span style="font-family: Verdana,Geneva,sans-serif;">Order ||< <span style="font-family: Verdana,Geneva,sans-serif;">Perciformes ||
 * < <span style="font-family: Verdana,Geneva,sans-serif;">Family ||< <span style="font-family: Verdana,Geneva,sans-serif;">Nandidae ||
 * < <span style="font-family: Verdana,Geneva,sans-serif;">Genus ||< <span style="font-family: Verdana,Geneva,sans-serif;">//Nandus// ||
 * < <span style="font-family: Verdana,Geneva,sans-serif;">Species ||< <span style="font-family: Verdana,Geneva,sans-serif;">//nebulosus// ||

<span style="font-family: Verdana,Geneva,sans-serif;">The Sunda Leaf Fish (//<span style="font-family: Verdana,Geneva,sans-serif;">N. nebulosus //)<span style="font-family: Verdana,Geneva,sans-serif;"> is one of the six species in the Asian leaf fish genus //<span style="font-family: Verdana,Geneva,sans-serif;">Nandus. //<span style="font-family: Verdana,Geneva,sans-serif;"> Wondering which species of leaf fish you saw in the reservoir or stream? Click on the link to dive straight to diagnosis.

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<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">**General Description**
<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Leaf fish are predatory fish with several recognizable features such as a laterally compressed body, cryptic coloration and strongly extensible jaws<span style="font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[7]. They are aptly dubbed "leaf fish" because of their ability to mimic dead leaves, both in appearance and behavior<span style="font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[6]. Leaf fish tend to be inactive, preferring to rely on their camouflage to ambush unsuspecting prey. <span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">__Below is a short video depicting how leaf fish hunt their prey and the speed of its strike:__ <span style="color: #000000; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">***Disclaimer:** The leaf fish depicted in this video are **__NOT__** the Sunda Leaf Fish (//Nandus nebulosus//) but Amazon Leaf Fish (//Monocirrhus polyanthus//). One notable difference is that the Sunda Leaf Fish lacks the threadlike extension on its lower lip that is present in Amazon Leaf Fish//.// media type="youtube" key="5wORJ7oJp6g" height="400" width="536" align="center"

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">**Species Description**
<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="font-family: Verdana,Geneva,sans-serif;">The Sunda Leaf Fish are well-adapted to thrive in the forest streams they inhabit. Its striking resemblance to a dead leaf as well as exceptionally well-developed predatory habits are perfectly designed for this ambush predator. Three aspects are highlighted here - Cryptic camouflage, mimicry behavior and extensible jaws. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="font-family: Verdana,Geneva,sans-serif;">

**<span style="font-family: Verdana,Geneva,sans-serif;">Cryptic Camouflage **
<span style="font-family: Verdana,Geneva,sans-serif;"> The Sunda Leaf Fish <span style="font-family: Verdana,Geneva,sans-serif;">is a master of disguise. It exhibits remarkable ability to masquerade as a floating piece of dead leaf. Being mottled with light and dark shades of brown allows it to blend among dead vegetation where it lays motionless, waiting to ambush any poten <span style="font-family: Verdana,Geneva,sans-serif;">tial prey that passes [10] <span style="font-family: Verdana,Geneva,sans-serif;">. This allows the leaf imposter to conserve energy as it does not need to pursue after its prey, which are typically fast moving small fish and shrimps that can dart away quickly from danger [10] <span style="font-family: Verdana,Geneva,sans-serif;">. The dark brown band that runs through its eye may function as a form of disruptive camouflage to avoid detection by breaking up the outline of this prominent feature.

<span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">

<span style="font-family: Verdana,Geneva,sans-serif;">**Mimicry Behavior**
<span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">When hunting, the Sunda Leaf Fish stalks its prey frontally and drifts towards it with its head slightly down<span style="color: #000000; font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[5]. By floating in the water with minimum movement of its fins, the predator mimics a dead leaf drifting in the current<span style="color: #000000; font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[5]. This behavioral adaptation enhances its cryptic camouflage and makes it even harder for its prey to detect it. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">



<span style="color: black; font-family: Verdana,Geneva,sans-serif;">**Extensible Jaws**
<span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Once it is close enough to its unsuspecting prey, the “dead leaf” strikes with incredible speed. Without jerking its body, its extensible jaws (premaxilla) slides out and reveals a large cavernous mouth. This forms a “suction tube” that engulfs its prey so quickly that it is all over within a split second<span style="color: #000000; font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[10].

<span style="display: block; font-family: Verdana,Geneva,sans-serif; font-size: 80%; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; font-size: 80%; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; font-size: 80%; text-align: justify;">*Some Rights Reserved. This work was obtained from the TLT Group, 10/11/11, at http://tltgroup.wordpress.com/low-threshold-applications/10-creating-low-threshold-animations-for-teaching-and-learning. The modifications or extensions offered here are licensed by Hou Zhisheng, NUS under a Creative Commons Attribution-Share Alike 3.0 United States License. Hou Zhisheng, NUS permits but does not endorse subsequent use of this work, provided that you in turn include attribution and this same share-it-forward licensing restriction.

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<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 140%;">Practical Fishkeeping
<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">**Challenging predators for the experienced aquarist** <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Although the Sunda Leaf Fish <span style="font-family: Verdana,Geneva,sans-serif;">is commonly available in the aquarium trade, it is a challenging fish that is not recommended for novice aquarists. Because of the unattractive cryptic coloration and shy, reclusive nature of the Sunda Leaf Fish//<span style="font-family: Verdana,Geneva,sans-serif;">, //<span style="font-family: Verdana,Geneva,sans-serif;"> it does not appeal to everyone. This is a demanding fish that requires considerations in tank setup, choice of tank mates and food. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">The Sunda Leaf Fish is a fairly timid fish that prefer to hide in shadows of a well-planted tank. Added to this, the leaf fish is far from the typical "community fish" that many novice aquarists desire. In fact, it would probably prey on its tank mates if given a chance. Given its insatiable appetite for live food, it is probably unadvisable to keep this fish unless you have a steady source of live fish or shrimps. This usually translates to high costs in rearing this fish.

<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">However, despite the difficulty of keeping this fish, its intriguing coloration as well as extremely well-developed predatory habits makes this a unique and exotic fish for serious aquarists who can meet its demands.

<span style="font-family: Verdana,Geneva,sans-serif; font-size: 110%;">Fact Sheet
<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">** Size: ** A medium-sized fish that grows up to 14 cm. **<span style="color: black; font-family: Verdana,Geneva,sans-serif;">Di<span style="font-family: Verdana,Geneva,sans-serif;">et: **<span style="font-family: Verdana,Geneva,sans-serif;"> The Sunda Leaf Fish <span style="font-family: Verdana,Geneva,sans-serif;">is a strict carnivore that feeds on small fish and shrimps (juveniles may feed on aquatic larvae as well). It is notorious for refusing to eat anything but live food [9] <span style="font-family: Verdana,Geneva,sans-serif;">. Aquarists should consider the costly investment (in money and time) in maintaining //<span style="font-family: Verdana,Geneva,sans-serif;">the leaf fish //<span style="font-family: Verdana,Geneva,sans-serif;"> with a steady supply of live food. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">** Habitat: ** Freshwater. Shallow forest pools, slow-flowing forest streams, swamps, bogs and larger water bodies including lakes and reservoirs<span style="color: #000000; font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[10]. <span style="color: #000000; font-family: Verdana,Geneva,sans-serif;">The leaf fish is a near-bottom to b ottom dweller<span style="color: #000000; font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[6]. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">** Water Conditions: ** //N. nebulosus// thrives in soft, acidic water (pH 4–6) at 24–28 °C (75°F). The addition of salt (as recommended by some aquarium literature) is unadvisable as it may have adverse effects on this purely freshwater fish<span style="font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[9]. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">**Aquarium Setup:** A well-planted aquarium layout with submerged vegetation and driftwood should be provided. Substrate comprising of leaf litter (e.g. beech and oak) is ideal for this fairly shy and reclusive fish<span style="color: #262626; font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[9]. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Care should be taken in the choice of tank-mates as the leaf fish is predatory<span style="font-family: Verdana,Geneva,sans-serif;">. Its tank mates should not be much smaller than the leaf fish //<span style="font-family: Verdana,Geneva,sans-serif;">, //<span style="font-family: Verdana,Geneva,sans-serif;"> or they would be regarded as prey items by it. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">** Breeding: **Oviparous. No other information is available about the detailed breeding habits of this species. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">** Natural Distribution: ** R anges from Thailand through Peninsular Malaysia and Singapore to Sumatra and Borneo. In Singapore, it is found in the Central Catchment Nature Reserve. media type="googlemap" key="http://maps.google.com/maps/ms?hl=en&mpa=0&ctz=-480&mpf=0&ie=UTF8&msa=0&msid=213059436361390743095.0004b15a1adcc51c0c346&t=p&vpsrc=6&ll=5.441022,108.369141&spn=30.268101,37.353516&z=4&output=embed" width="466" height="384" align="center"

<span style="font-family: Verdana,Geneva,sans-serif;">** Did you know? **

<span style="color: #000000; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"><span style="font-family: Verdana,Geneva,sans-serif;">Although rarely seen, <span style="color: #000000; font-family: Verdana,Geneva,sans-serif;">the Sunda Leaf Fish is nati ve to Singapore. According to Alfred (1966), the first record of //N. nebulosus// was by Bleeker (1860) on the basis of a drawing submitted to him by Count Francis De Castelnau who was residing in Singapore. This record was only verified __after approximately 100 years__ when the species was re-discovered in 1962 [1].

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<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 140%;">Conservation
<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">**Status & Threats:** Sadly, this unique fish is now listed as '<span style="color: #ff1414; font-family: Verdana,Geneva,sans-serif;">Critically Endangered ' in Singapore [3]. It is, however, not evaluated by IUCN. According to the Singapore Red Data Book (2008), //N. nebulosus// faces threats from habitat degradation and illegal collection. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">**Conservation Measures:** The Singapore Red Data Book (2008) urges the "continued protection of its natural habitat in the Central Catchment Nature Reserve from human impacts." <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">**What can you do to help?** Since these fish thrive in pristine freshwater habitats with little disturbance, please do not attempt to capture or disturb the leaf fish. Leaf them alone! Also, you can play a vital role in conservation of our nature reserves by taking good care of it! (e.g. not littering) = =

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<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">Why diagnose?
<span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="color: black; display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Inclusive of //Nandus// //nebulosus//, a total of six //Nandus// species that have been described<span style="color: #000000; font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[8] :
 * 1) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">**// Nandus nebulosus // Gray 1835 **
 * 2) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">// Nandus nandus // Hamilton 1822
 * 3) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">// Nandus oxyrhynchus // Ng, Vidthayanon & Ng 1996
 * 4) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">// Nandus prolixus // Chakrabarty, Oldfield & Ng 2006
 * 5) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">//Nandus andrewi// Ng & Jaafar 2008
 * 6) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">//Nandus mercatus// Ng 2008

**<span style="font-family: Verdana,Geneva,sans-serif;">//Nandus nebulosus// **<span style="font-family: Verdana,Geneva,sans-serif;"> and //<span style="font-family: Verdana,Geneva,sans-serif;">N. nandus //<span style="font-family: Verdana,Geneva,sans-serif;"> are more commonly found in the aquarium trade, with //<span style="font-family: Verdana,Geneva,sans-serif;">N. andrewi //<span style="font-family: Verdana,Geneva,sans-serif;"> as a rare import<span style="font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[10]. Different species may have slightly different water requirements. For example, **//N. nebulosus//** prefers more acidic water conditions than //N. nandus// [10]. As such, it might be important to differentiate **//N.// //nebulosus//** from the other //Nandus// species so as to ascribe proper care.

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">Distinguishing Features
<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> The shape of the snouts are typically used to distinguish between //Nandus// species, with **//N. nebulosus//** having a short snout<span style="font-family: Verdana,Geneva,sans-serif; vertical-align: super;">[7]. <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">However, **<span style="font-family: Verdana,Geneva,sans-serif;">//N. nebulosus// ** bears striking resemblance to //<span style="font-family: Verdana,Geneva,sans-serif;">N. mercatus //<span style="font-family: Verdana,Geneva,sans-serif;">and snout profile might be insufficient for diagnosis //<span style="font-family: Verdana,Geneva,sans-serif;">. // The position of the rostral fossa can also help differentiate the two [8]. While the rostral fossa always reaches to more than half the distance between the tip of the snout and base of the first dorsal-fin element in **<span style="font-family: Verdana,Geneva,sans-serif;">//N. nebulosus// **, it only reaches to almost half the distance in //N. mercatus// [8] //.// For more details on the diagnosis, please refer to the key below.





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<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 110%;">**Key to //Nandus// species**
<span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">An updated key to the //Nandus// species was published by Ng (2008). In summary, //N. nebulosus// can be differentiated by the following four characteristics:
 * 1) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Body mottled brown in life and upon preservation
 * 2) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Distinct dark spot on caudal peduncle absent; total lateral line scales 24-42
 * 3) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Anterior lateral-line scales 22–25
 * 4) <span style="display: block; font-family: Verdana,Geneva,sans-serif; text-align: justify;">Snout short (20.1–25.9% Head Length); posterior tip of rostral fossa more than halfway between tip of snout and base of first dorsal-fin element

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<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 140%;">Related Links
Ecology Asia FishBase Tropical Fish Finder

<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 140%;">Comments
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<span style="font-family: Tahoma,Geneva,sans-serif; font-size: 140%;">**References**
<span style="display: block; font-family: Verdana,Geneva,sans-serif; font-size: 90%; text-align: left;"> <span style="display: block; font-family: Verdana,Geneva,sans-serif; font-size: 90%; text-align: left;"> 1. Alfred, E. R. (1966). The Fresh-Water Fishes of Singapore. Zoologische Verhandelingen, Leiden, Number 78, 68 pages, 8 plates. 2. Chakrabarty, P., Oldfield, R. G. and Ng, H. H. (2006). //Nandus prolixus//, a new species of leaf fish from northeast Borneo (Teleostei: Perciformes: Nandidae). //Zootaxa//. 1328, 51–61. 3. Davison, G. W. H., Ng, P. K. L. and Ho, H. C. (2008). The Singapore red data book: threatened plants & animals of Singapore. Nature Society (Singapore). 285 pp. 4. Inger, R. F. and Chin, P. K. (2002). The fresh-water fishes of North Borneo. Kota Kinabalu, Sabah, Malaysia :Natural History Publications (Borneo). 5. Liem, K.F. (1970) Comparative functional anatomy of the Nandidae (Pisces: Teleostei). Fieldiana: Zoology, 56, 1–166. 6. Lim, K. P. and Ng K. L. (1990). A Guide to Freshwater Fish of Singapore. (http://habitatnews.nus.edu.sg/guidebooks/freshfish/text/203.html) 7. Ng, H. H. and Jaafar, Z. (2008). A new species of leaf fish, //Nandus andrewi// (Teleostei: Perciformes: Nandidae) from northeastern India. //Zootaxa//. 1731, 24–32. 8. Ng, H. H. (2008). //Nandus mercatus// (Teleostei: Perciformes: Nandidae), a new leaf fish from Sumatra. //Zootaxa//. 1963, 43–53. 9. Ng, H. H. (2010, September 1-30). How do I keep Nandus? //Practical Fishkeeping.// Retrieved Nov 1, 2011, from http://www.practicalfishkeeping.co.uk/content.php?sid=74 10. Yeo, D. C. J., Wang, L. K., Lim, K. K. P. (2010). Private lives : an exposé of Singapore's freshwaters. Singapore : Raffles Museum of Biodiversity Research, National University of Singapore.