There has been an ongoing census of the fish community in Lake Tanganyika for the last twenty years. During this census the Japanese scientists have taken note of some rather drastic changes in the fish populations. These findings were published in the most recent issue of the journal “Ecology of Freshwater Fish”.

The conclusions were reached by Yuichi Takeuchi and team, while surveying the density and number of the different fish in Kasenga Point, at the southern end of Lake Tanganyika between 1988 and 2008.

The investigative team, headed by Yuichi Takeuchi, took note of a total of 54 chichlid and six non-cichlid species of fish, over the period of the survey. The most abundant type of fish recorded were the aufwuchs feeders.

Even though there was an abundance of fish and no lack of number of species present, their research indicates that there was a steep decline in the density of the aufwuchs feeders and invertebrate eaters during the course of the study. In a strange turn of events, there was an increase in the density of detritus feeders during this time.

The researches theorize that the change in the fish community could be due to human activities in the area such as deforestation, and agriculture run offs, which would lead to sediment loading in Lake Tanganyika to increase.

While they could not completely rule out natural variation for these changes in the fish community of Lake Tanganyika, there is no doubt that human activity is also making a large impact on the area as well.

Apparently, and hardly supprising for any one who kept fish for some time, the old belief that a fish only has a three second memory is complete balderdash. In fact scientists have discovered that fish actually do have quite a good memory, and can actually be quite smart. They have also been noted to be capable of working in a team, and even acting quite deviously.

One scientists, Dr. Kevin Warburton, who has been engaged in research on the subject for many years, has discounted the whole three second fish memory idea, as “absolute rubbish”.

Fish have been discovered to be far more clever, than was previously thought.

Dr. Warburton expounded, “’Fish are quite sophisticated. Fish can remember prey types for months. They can learn to avoid predators after being attacked once and they retain this memory for several months. And carp that have been caught by fishers avoid hooks for at least a year. That fish have only a three second memory is just rubbish.”

Dr. Warburton’s research has been focused on the freshwater fish of Australia, and has been taking a look at how Silver Perch actually learn how to handle the varying kinds of prey they come into contact with.

He has also said that the fish seem to exhibit human behavior in some instances. “Some behavioral traits that we think are very human, such as deception, fish have as well,” Dr. Warburton explains,

“Fish can recognize other individuals and modify their own behavior after observing interactions between other individuals. For example Siamese fighting fish will attack other members of the same species more aggressively if they’ve seen them lose contests with other fighters.”

It has been noted that in reef environments that cleaner fish remove and eat parasitic organisms off of larger “client” fish. “But what’s fascinating is that they co-operate more with clients when they are being observed by other potential clients.” Dr. Warburton added. ‘This improves their ‘image’ and their chances of attracting clients. Some cleaners co-operate with small clients to raise their image so as to deceive larger clients, which they then cheat on by biting them rather than removing their parasites.”

The fish even take a second look at potential predators to see how much of a risk they pose. “For added safety, they often do this as co-operating pairs, with the two fish taking the lead alternately. They will approach predators most closely when they have co-operated in previous inspections.” he explained.

Some minnows will even recognize a dangerous environment by associating a certain smell in the water with “alarm” chemicals that are released by other minnows who were felled by a predator.

This just goes to show you, that fish not only are not as affable as we once thought them to be, but actually have an intricate social structure, advanced forms of communication, and can literally swim circles around their prey. This we need to re-evaluate our entire conception of these creatures.

Above you can see a fascinating video of squat Urchin shrimp and below you find some basic information about this tiny shrimp.

The squat Urchin shrimp, known in scientific circles as Gnathophylloides mineri, is quite a fascinating invertebrate that many aquarists would often look over, or even never see.

This fascinating little creature is only milometers in length, and it survives in its own little world, not seeming to care about how the rest of the Sea Urchins live. These Sea Urchins actually live ON TOP of other Sea Urchins!

The Squat Urchin Shrimp is incredibly tiny, often never reaching more than 6mm in length, and it often orients itself parallel with their hosts spines, which not only protects it from becoming lunch for some other sea critter, but also makes it nigh on impossible to see, some would even say it’s effectively invisible to the naked eye. Colonies of these little guys often have numbers ranging from a few to a half dozen will share the same host Sea Urchin. Not only does it seek protection from its hosts spines, it actually feeds on them, proving once again just how successful this tiny creature is at surviving. This is a rather odd kind of parasitism, as it does not have any ill effects for the host.

The Squat Urchin Shrimp also will take every chance they get to feed upon the detritus that the host sea urchin picks up off the ocean floor on it’s travels.

The male molly fish, found in Mexico, sports a “sexy” moustache, so that it might appear more attractive to females of the species.

Scientists were completely baffled as to why this strange Mexican fish would have a rather elaborate moustache-like structure on their top lip.

Some light has now been shed on the subject, it has been found that this “moustache” is actually sexually attractive to potential mates, and it is likely a key factor in the mating process.

Not only does this frisky molly fish use its moustache for show, but it may also be used in a kind of fish foreplay, exciting females by rubbing their genitals.

The details of this are published in the journal Behavioral Ecology and Sociobiology.

As the name suggests, Mexican mollies make their home in Mexico, living in a range of locations from creeks, to lakes, and even small rivers.

Mexican mollies have a rather complex mating behavior, with the males fertilizing the females internally, rather than just spraying their sperm over externally laid eggs, like so many other fish species.

Mine is Bigger Than Yours!

Not all male Mexican mollies are created equal however. Some of them have a moustache-looking structure jetting up from the scales on their top lip.

Until quite recently, the function of this moustache has not been known, and no one has bothered to look deeper into the matter.

So a crack team of scientists, which include Professor Ingo Schlupp of the university of Oklahoma, collegues in the US and Germany have decided to delve into it for the first time.

They trapped a wide selection of both male and female Mexican mollies, to measure the length of the moustache on those that had one.

They then proceeded to run a myriad of tests, and females consistently preferred males with moustaches over ones without. Of course, the bigger the moustache the more attention the males received.  This shows once and for all, that the barrier between fish and man.. Is not so great after all.

Hanky Panky in the Tank:

Even though the group has only tested the visual attractiveness of the moustache, there is evidence to suggest that it also plays a more tactile role. Professor Schlupp has told the BBC “This is based on the general observation that males will touch the female’s genital region with their mouth prior to mating,”

This unusual behavior has become known as “nipping” and is being pursued diligently by the group of scientists.

The common consensus is that by rubbing their moustache on the genitalia of the females, they are simply advertising their attractiveness. Some other species of catfish have comparable features, and have unknown functions.

Some scientists have also speculated that this moustache may act to attract more food as well, which is a desirable trait in the fish kingdom.

The group will continue to study the Mexican Molly’s moustache, until then, it will have to be boiled down to sex appeal.



Sounds weird? If so you haven´t heard about the ”fish mail box” in Inada Park, Kawasaki, Tama River in Japan near Tokyo. The ”fish mail box” is a 7 meter by 4 meter large concrete water tank that have been placed along the river to give people a place to drop unwanted fish. The goal of the fish box is to prevent people from releasing fish into the river, since foreign species can wreck havoc with local ecosystems.

People are encourage to call before they drop off their pets as fish can die from the shock if not acclimatized correctly, but it is is permitted to just drop off fish as well. People are also encouraged to drop off tropical invasive species they catch in the river in the fish box.

The fish left in these fish boxes are cared for by Mitsuaki Yamasaki, 51, the head of a local river fish association, before they are placed in new homes. The box is receiving about 10,000 fish a year ranging from small fish to large gars.

The Tama River has seen a lot of new species released in it in recent years during which the aquarium hobby has become even more popular in Japan than before. This has in no small part to do with the movie “Finding Nemo”, even if the increase in popularity started before the movie was released. More than 200 species of foreign tropical fish have been found in the Tama River ranging from typical aquarium fish such as guppies and angelfish to less frequently kept creatures like piranhas and arowanas, earning it the nick name the Tamazon River. Some of the tropical species have established breeding populations while others haven´t, but most species can survive the winters by staying near water treatment areas along the river.

Mitsuaki Yamasaki and other members of the local river fish association are afraid that breeding populations of gars will establish themselves in the river since more and more gars are sold and they have been found in the river. Gar species are predatory fish that could have a severe negative impact on native fish such as sweetfish . Gars are likely able to establish breeding populations in a river with the conditions of the Tama River.

It can not be denied that with over 10,000 fish received by one of these fish boxes since it opened the initiative could aid the struggle to prevent invasive species from getting a foothold in local waters, and it might be an idea that deserves being tried in other problems areas around the world, such as Florida. The only question is if projects like this could work with out the devotion and support from people like Mitsuaki Yamasaki, people who are really passionate about what they do.

Any one interested in or planning to start a similar project somewhere else is very welcome to contact us here at AquaticCommunity as we would love to document your work getting the project of the ground and running it. Leave a comment in the commentary field or send an e-mail to admin@aquaticcommunity.com.

Two suspects have been arrested in connection with the bludgeoning of dozens of Koi fish at San Joaquin Delta College in Stockton, California.

Surveillance cameras captured two men beating the fish, who was living in a pond on campus, with baseball bats.
13 Koi fish have died so far and several others are injured after the attack.

In south-east Asia and northern Australia, Archer fish can be seen spitting jets of water up to three meters to knock out insects and spiders and make them fall into the water. Archer fish does for instnace help control the populations of mosquitoes and flies.

In captivity, insects in the air can be scarce – especially during the chilly Bristol winter. That is why a shoal of archer fish living at Bristol’s Blue Reef Aquarium have been given a mobile dotted with plastic flies for target practise.

The archers living in the aquarium are roughly 1.5 years of age and staff said that their natural hunting instinct may have become rusty. To combat this, the staff is now smearing the fake flies with bloddworm so that when a fish manages to hit a fly, tasty bloodworm falls down into the water.

“In the summer if we have some insects flying around I’ll be surprised if they don’t go for them,” said senior aquarist Lindsay Holloway.

A recent study has unveiled that the King demoiselle (Chrysiptera rex) is actually three different species that recently diverged from each other.  (picture)

“This work, along with others, is starting to show that there is a lot more biodiversity in the oceans then we previously thought,” said Joshua Drew, a marine conservation biologist at the Field Museum of Natural History in Chicago and a member of the demoiselle study. “We really are in a situation where we are losing things before we even know they exist.”

The King demoiselle comes in a wide range of colours and patterns, but this alone is not enough to consider it several species. There are plenty of examples of fish that look very dissimilar from each other while still belonging to the same species.

However, what Dews’ colleagues discovered while doing field research in Southeast Asia was that the differences in appearance seemed to be linked to distinct geographical regions. In order to find out more, they decided to ship about a dozen King demoiselle samples to Drew, collected from three separate populations in Indonesia, the Philippines and the South China Sea.

In his laboratory, Drew analyzed the genetic composition of the samples, focusing on three different genes – one that has evolved slowly and two that have changed quickly over the years. What Drew found out was highly interesting: the two fast changing genes differed in the three geographical groups, but not the one slow changing one. This indicates that from an evolutionary perspective, the three groups diverged from each other quite recently.

“That means that this little fish we thought was broadly distributed has a mosaic of individual populations and each one is genetically distinct,” Drew explained. “That highlights how little we really know about how biodiversity on Earth is distributed.”

Earlier, scientists assumed that it was difficult for distinct populations of reef fish to form if they had small larvae easily caught by currents. It seemed reasonable to presume that larvae from many different geographical locations would intermingle with each other throughout the sea. New data, obtained from studies like the King demoiselle one, do however suggest that larvae often settle close to its point of origin.

The King demoiselle study will be published in the journal Coral Reefs.

http://springerlink.metapress.com/content/100407/?p=32f929fa7f60452da6d63226ec8898a6&pi=0

If you’re into interior design, you have probably encountered the online tools that allow you to try different types of interior designs online without breaking a sweat. With a simple drag and click you can move around heavy sofas, rearrange book shelves and try out 54 different types of rug.

But did you know that there is a very similar tool has been created for all the aquarium aficionados out there: the AquaSketcher. You start out by picking out an item, e.g. a plant, piece of wood or nice rock from a list, and then proceed to choose its colour, dimensions etc. Last but not least, you start placing your objects in the aquarium to see how well they go together. You can naturally go back and change things, gradually building towards the perfect setup.

Naturally, a tool like this has its limitations. Just as the tools developed for interior design it will only give you a hint about the final results, and it will naturally be impossible to find a plant, root or rock that looks exactly as in the picture. Also, you have to keep in mind that factors such as light play no small part in how we perceive a room or an aquarium. In an aquarium, water movements will also be of importance. Perhaps a later version of the AquaSketcher will allow you turn on your imaginary filter system to see the plants move with the current?

If you want to give the AquaSketcher a try you can find it here:

For the first time, a viral hemorrhagic septicemia virus (VHSV or VHSv) has been identified in fish from Lake Superior, the largest of the five Great Lakes of North America.

The virus was identified by researchers at the Cornell University’s College of Veterinary Medicine and the finding has also been confirmed by the United States Geological Survey’s (USGS) Western Fisheries Research Center in Seattle.

The virus causes viral hemorrhagic septicemia (VHS) in fish and can result in significant losses in wild and captive raised fish populations.

“VHS is one of the most important diseases of finfish,” says James Winton, a VHSV expert working at the Western Fisheries Research Center. “It not only affects the health and well-being of populations of several important native fish species, but it can also impact trade, and, should it spread into the U.S. aquaculture industry, could do substantial damage as happened in Europe and parts of Japan.”

The infection is one of only nine fish diseases that must be reported to the World Organization for Animal Health. Until 2005 it was not known to exist in the Great Lake system but that year it caused several massive die-offs. Since then the virus has been detected in all of the Great Lakes except Lake Superior, and was for instance the culprit when 40,000 freshwater drums died in Lake Ontario over the course of just four days. In addition to the Great Lakes, the virus is also present in the rivers of Niagara and St. Lawrence and in inland lakes in New York, Michigan and Wisconsin.

Previous genetic research carried out by scientists in Canada and the United States show that the VHS virus was probably introduced to the Great Lakes during the last 5-10 years.

Experts now fear that current federal and state restrictions placed upon the movement of fish and fish products won’t be enough to prevent the virus from reaching native fish in the 31 states of the Mississippi River basin.