Kaix
07-28-2006, 09:20 AM
Size does matter, in this case, the smaller the better. A fish initially thought to be a fry is now a contender for the world’s smallest fish title
Fully mature females have been documented to be 7.9 mm in size, which is about the size of a mosquito. Should the claim be universally accepted, this also makes it the smallest recorded vertebrate.
The fish was actually discovered over a decade ago in 1995, in the peat swamps on the Indonesian island of Sumatra by a Singapore team. This included Associate Professor Peter Ng, museum director of the Raffles Museum of Biodiversity Research, National University of Singapore (NUS). Upon netting the fish, he said that it was so small that his team thought it was only a fish fry and so it was not thoroughly examined.
So specimens were preserved and kept at the Raffles Museum until 2003, when Research Officer, Dr Tan Heok
Hui, came across it while checking on the collection. And it was only recently that the findings were published in the online edition of the scientific journal Proceedings of the Royal Society: Biological Sciences.
The report “Paedocypris, a new genus of Southeast Asian cyprinid fish with a remarkable sexual dimorphism, comprises the world’s smallest vertebrate” is credited to Maurice Kottelat and Tan Heok Hui, Raffles Museum of Biodiversity Research, NUS; Ralf Britz, Department of Zoology, The Natural History Museum, and Kai-Erik
Witte, Max Planck Institute of Developmental Biology.
Interestingly, the skinny, scaleless and transparent Paedocypris progenetica is part of the carp family. Dr Tan tells AQM that its maximum size is less than 10mm. He adds that the fish has reduced bone structures, with rudimentary skull bones that leave its brain partially uncovered.
Dr Tan mentions that the other interesting characteristics of the fish include retention of larval features: long pre-anal skin fold; sexual dimorphism, enlarged muscles for the male’s pelvic fin attachment and highly modified pelvic fins of males (possibly to be used for reproductive purposes).
According to the published findings, this tiny fish can be found in slow-flowing blackwater streams or pools in peat swamp forests. The fish seems to thrive in very acidic water, as these swamp waters have a pH value of 3.0, which is at least 100 times more acidic than rainwater.
P. progenetica inhabits the deeper, cooler water layers. And it was found to be only in shaded areas in primary
or secondary forest, but not in light-exposed open areas.
Its diet consists mainly of planktonic rotifers and cladocerans.
Agreeing that such a fish is more suited for a very small niche market is Kenny Yap, Executive Chairman and Managing Director of Qian Hu. He tells AQM that he thinks the fish is good for exhibition, but not for the mass market.
Unfortunately, the peat swamp forests in Southeast Asia, where these unique fish can be found, are quickly disappearing. This is the result of logging, urbanisation and conversion of land for agricultural use in those areas. The article in the scientific journal also mentioned that many of the peat swamps that the team had surveyed no longer exist and their fauna has been eradicated.
Which is the Smallest?
The claim to being the smallest fish in the world has sparked off heated competition from other claimants.
Ted Pietsch, a professor of aquatic and fisheries sciences at the University of Washington, has claimed that a deepsea angler fish found in the Gulf of Panama is actually smaller than Paedocypris progenetica.
A sexually mature male Photocorynus spiniceps has been measured at just 6.2 mm in length. And this, he says, should be considered the world’s smallest.
However, P. spiniceps is described as an ectoparasite and a sexual parasite, as it attaches to the body of the much larger (4.9cm - long) female, and fuses to its mate for life, whereas, the male and female P. progenetica are free-swimming individual fishes.
Another fish vying for the title is the stout infantfish (formally identified as Schindleria brevipinguis). Measuring an average of 7.11 mm for males and 8.32 mm for females, it was discovered by Australian scientists in 1979, but was only classified in 2004.
The fish is described as a scaleless, wormlike thread with big eyes, no teeth or pigmentation. It was caught off Australia’s east coast. Australian researchers say the fish is so small that it would take a million of them to weigh just one single kilogram.
It seems that debate on which fish really is the smallest will keep going on and on, as there are certain complexities when it comes to measurement. It is very difficult to determine smallness with there being three standard measurements: weight, volume and length. So, in this case, does it mean that the smallest fish is the shortest, the lightest or the one which has the smallest volume? That has yet to be determined.
And at the end of the day, Dr Brtiz told the BBC that the fish were all interesting and unusual, and needed more detailed study, and that the question on which is the smallest was really not a scientific issue, but a popular one.
Fully mature females have been documented to be 7.9 mm in size, which is about the size of a mosquito. Should the claim be universally accepted, this also makes it the smallest recorded vertebrate.
The fish was actually discovered over a decade ago in 1995, in the peat swamps on the Indonesian island of Sumatra by a Singapore team. This included Associate Professor Peter Ng, museum director of the Raffles Museum of Biodiversity Research, National University of Singapore (NUS). Upon netting the fish, he said that it was so small that his team thought it was only a fish fry and so it was not thoroughly examined.
So specimens were preserved and kept at the Raffles Museum until 2003, when Research Officer, Dr Tan Heok
Hui, came across it while checking on the collection. And it was only recently that the findings were published in the online edition of the scientific journal Proceedings of the Royal Society: Biological Sciences.
The report “Paedocypris, a new genus of Southeast Asian cyprinid fish with a remarkable sexual dimorphism, comprises the world’s smallest vertebrate” is credited to Maurice Kottelat and Tan Heok Hui, Raffles Museum of Biodiversity Research, NUS; Ralf Britz, Department of Zoology, The Natural History Museum, and Kai-Erik
Witte, Max Planck Institute of Developmental Biology.
Interestingly, the skinny, scaleless and transparent Paedocypris progenetica is part of the carp family. Dr Tan tells AQM that its maximum size is less than 10mm. He adds that the fish has reduced bone structures, with rudimentary skull bones that leave its brain partially uncovered.
Dr Tan mentions that the other interesting characteristics of the fish include retention of larval features: long pre-anal skin fold; sexual dimorphism, enlarged muscles for the male’s pelvic fin attachment and highly modified pelvic fins of males (possibly to be used for reproductive purposes).
According to the published findings, this tiny fish can be found in slow-flowing blackwater streams or pools in peat swamp forests. The fish seems to thrive in very acidic water, as these swamp waters have a pH value of 3.0, which is at least 100 times more acidic than rainwater.
P. progenetica inhabits the deeper, cooler water layers. And it was found to be only in shaded areas in primary
or secondary forest, but not in light-exposed open areas.
Its diet consists mainly of planktonic rotifers and cladocerans.
Agreeing that such a fish is more suited for a very small niche market is Kenny Yap, Executive Chairman and Managing Director of Qian Hu. He tells AQM that he thinks the fish is good for exhibition, but not for the mass market.
Unfortunately, the peat swamp forests in Southeast Asia, where these unique fish can be found, are quickly disappearing. This is the result of logging, urbanisation and conversion of land for agricultural use in those areas. The article in the scientific journal also mentioned that many of the peat swamps that the team had surveyed no longer exist and their fauna has been eradicated.
Which is the Smallest?
The claim to being the smallest fish in the world has sparked off heated competition from other claimants.
Ted Pietsch, a professor of aquatic and fisheries sciences at the University of Washington, has claimed that a deepsea angler fish found in the Gulf of Panama is actually smaller than Paedocypris progenetica.
A sexually mature male Photocorynus spiniceps has been measured at just 6.2 mm in length. And this, he says, should be considered the world’s smallest.
However, P. spiniceps is described as an ectoparasite and a sexual parasite, as it attaches to the body of the much larger (4.9cm - long) female, and fuses to its mate for life, whereas, the male and female P. progenetica are free-swimming individual fishes.
Another fish vying for the title is the stout infantfish (formally identified as Schindleria brevipinguis). Measuring an average of 7.11 mm for males and 8.32 mm for females, it was discovered by Australian scientists in 1979, but was only classified in 2004.
The fish is described as a scaleless, wormlike thread with big eyes, no teeth or pigmentation. It was caught off Australia’s east coast. Australian researchers say the fish is so small that it would take a million of them to weigh just one single kilogram.
It seems that debate on which fish really is the smallest will keep going on and on, as there are certain complexities when it comes to measurement. It is very difficult to determine smallness with there being three standard measurements: weight, volume and length. So, in this case, does it mean that the smallest fish is the shortest, the lightest or the one which has the smallest volume? That has yet to be determined.
And at the end of the day, Dr Brtiz told the BBC that the fish were all interesting and unusual, and needed more detailed study, and that the question on which is the smallest was really not a scientific issue, but a popular one.