My Mudskipper And Fiddler Crab Paper

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May 31, 2015
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This is a paper I had to do for school. I though it would be nice to post it on TFF. I researched mudskippers and fiddler crabs a lot before so this is what I chose to do it on.  If anything is incorrect please tell me. Enjoy.
Fiddler Crabs​
by Gnoflet​
   So let's say you’re a fish keeper and have set up have a fresh water tank and want some new fish.You start looking around online and find this kind of weird fish
that some people say can walk on land. But what is this fish? And why do some people say that it lives in freshwater and others saltwater (or marine water) and
still others brackish? And what is this brackish water that every one is talking about?
   Brackish water is where freshwater and marine water come together. Scientifically speaking,pure freshwater has a specific gravity (SG) of 1.000. SG is the
measurement of salt in the water. Brackish water starts at a SG of 1.005 and goes up to 1.020. Marine water has a SG of 1.020 and up the average brackish water
ranges from around a SG of around 1.008-1.010. This ‚Äúweird fish that¬†walks on land‚ÄĚ is a Mudskipper. Mudskippers reside in a SG of around 1.005-1.015.
Mudskippers grow to a average of around 6-12 cm. 2.5-4.75 in.) but some can be much smaller and others much larger.They have a lifespan of around five years.
They have a light grayish-brown body with prominent eyes, which are eyes that turn at will. They keep their eyes moist on land by bringing them back into their
eye sockets. These awesome fish swim in low levels of water near the shore and spend most of their time on shore. Around ninety percent of their life is spent on
the land. Mudskipper are native to the Indo-Pacific, from Africa to Australia and even to Polynesia. They live in the mangrove swamps that form when the roots of
mangrove trees catch sand and dirt carried down by freshwater rivers to the ocean. This causes small swamps to form.
   Mudskippers go on land to eat, spawn, and fight. When they are on land these fish retain water in their gills so they can breath, yet they can also breath through
their skin. They also must keep¬†their skin wet so they can acquire oxygen through it. To do this they roll in the mud every few¬†‚Äústeps.‚ÄĚ Because of its ability to ‚Äúwalk‚ÄĚ
on land with its pectoral fins, a Mudskipper can and will eat the tiny algae, worms and crustaceans that live upon the land in the mangrove swaps. Most of the time
it will filter through the mud with special organisms located near its mouth and sift out the small plants and animals. After that it ejects the mud and eats what it has
found. When it eats the Mudskipper¬†must drop its water store, so it has to be constantly restored. To have a secure place to restore water¬†they dig a ‚ÄúU‚ÄĚ shaped tunnel
using their mouth as a shovel, which they also use as a place to hide from predators,(such as Monitor Lizards), a breeding place(see next paragraph), and a kind of
territory marker.
   When they go up on land to breed the males show off their dorsal fins to the females. Because Mudskippers are so small they also must jump to be noticed. After
they locate a mate they enter their burrow and swim to the special chamber of air in the back of it. There the female lays her eggs so the eggs can have oxygen. But
the oxygen does not last for long so the male must go to the other end of the tunnel, gulp some air, bring it back to the chamber, release it, and go back again. This
process is repeated consistently until the eggs hatch.
   Mudskippers are kept in aquariums and tanks in captivity. They are not often sold by pet shops so most people have to order them online. Breeding in aquariums
and tanks is very rare and almost unknown; because most people do not have the natural tides and mangrove roots to replicate the natural environment.
Mudskippers' tanks must be very humid to keep the skin wet and large [SIZE=medium]enough to hold both a [/SIZE][SIZE=medium]large[/SIZE][SIZE=medium] amount of land and a[/SIZE] decent [SIZE=medium]amount of water. They are often [/SIZE]
[SIZE=medium]kept with [/SIZE]figure eight puffer fish, green spotted puffer fish, archer fish, and fiddler crabs. Some people make the mistake of putting a brackish water fish in a fully
freshwater aquarium or a fully marine aquarium. Because these fish are fish are not designed to tolerate theses conditions they usually will die within a month.
   Fiddler crabs are another brackish water animal. They receive that title due to the males having [SIZE=medium]one large claw and one smaller claw which looks remotely like a [/SIZE]
[SIZE=medium]fiddle and bow. They require[/SIZE][SIZE=medium] [/SIZE][SIZE=medium]this big [/SIZE]claw to fight and attract females. This claw is useless for eating because of its huge, impractical size. If the lager claw breaks
off the smaller claw will grow to the size of the larger claw and they other claw will grow back as the smaller claw. Like Mudskippers Fiddler Crabs reside mangrove
swaps, and although they aren’t similar to Mudskippers or even fish, they share many of the same requirements.In fact they often live side by side in both their
native habitat and the home aquarium.
   Being invertebrates, they have different behaviors than Mudskippers, even though they both require similar water conditions. Like Mudskippers, Fiddler Crabs “eat
mud‚ÄĚ by picking it up with their claws and placing it within chambers near their mouths to filter¬†out microscopic plants and animals, but instead of getting rid of the
mud in a wet form, he drys it into a small compact pellets and then gets rid of it. Also like Mudskippers, Fiddler Crabs have gills, not lungs. They must keep these
gills moist to breath. They can get some water from their surroundings, but mostly they just enter the water to replenish the moisture store . They often dig burrows
to breed in and mark territory. To attract females a male Fiddler Crab will wave its claw around in a kind of¬†‚Äúdance‚ÄĚ. Each species of Fiddler Crab has a different
‚Äúdance‚ÄĚ so a female will not have trouble finding¬†the right species of mate. The female picks a mate based on two factors: the size of the claw, and the¬†quality of the
‚Äúdance‚ÄĚ. If a female gets close to a male's burrow he will try to get nearer to her and¬†draw her into his burrow. Once a female has chosen a mate they will stay
together until they go to the males burrow where they can mate without being disturbed.
  Even though the brackish water category is the smallest category of water it has many different kinds of fish and invertebrates other then the two we have covered.
I find most all of these fascinating. Although some, like the Mudskipper and Fiddler Crab, share many of the same behaviors and habitats they are each unique in 
design. I find it amazing that although Mudskippers and Fiddler Crabs are entirely different they can do many of the same things but most of the time
in different ways.

~The Complete Aquarium by Peter W. Scott
~Tropical Aquarium Fish by John Dawes
~ Planet Doc Documentaries On
 for reading.


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