why dont fish get pressure when they are at the bottom of the sea?
343798
cos they smoke sea weed
303722
Most of the time it's accidental.  They are scooping up food that are close to the shore...low and beyhold the water is too shallow and they find themselves ashore.
429160
At a higher elevation the pressure on the water is less therefore it will boil at a lower temperature than it would at sea level.\n\nA liquids state of matter depends on pressure and temperature to make something from liquid to gas you use high temperature and low pressure.
661803
Because of the pressure of water is more at the bottom of the dam. Think of the tonnes of water the dam is holding at the base. \n\nHope this helps...
448554
they use gills. the gills are filled with lots of blood vessels.  the fish draws in water from the mouth, which passes by and out the gills. as the water moves by, the blood cells take in oxygen and the waste gases are released.
190723
water pressure is dependent on depth and density of the liquid, it is dependent on depth because if you are in deep that means there is more water on top of you. similarly atmospheric pressure is also about height, we can say this because pressure near sea surface is more than that of on top of the himalayas. This is because there is more air above you when you are near the sea surface.
56609
They don't swallow the water, per se - they simply swim and let the water flow past their gills.  As the water flows throughout the network in their gills, the oxygen that's dispersed throughout the water enters their bloodstream, thus enabling the fish to breathe underwater!\n\nThis is why when one purchases a fish tank, one has to get an oxygen supplier as well - no fish can survive in just standing water for long!
29859
The tissues and cells of creatures that inhabit the deep oceans are filled with fluid and thus air space is significantly minimized . Air is subject to compression, whereby a fluid such as water cannot be compressed.\n\nWithout internal compression, the creatures have negated the potential external pressure of the depths.
520263
Well, their respitory system like their circulatory system allowed fish to live in the water for their entier lives. Most animals would die under the extreme water pressure and lack of breathable oxygen, but fish were able to adapt to live in the water.
718005
Mainly their thick outer layer of blubber is able to absorb a lot of the pressure.  Their immense size does help even it out.  Unfortunately, even though they are built to be able to dive that deeply, it's not a harmless thing.  Whales do get the bends.  Often whale bones, especially those of sperm whales, show signs of nitrogen bubbles in the blood and tissues.  Over time it does cause them pain and in some rare cases some deformity.  So they're designed to be able to do it, but it is not risk-free to the whale.  There is a biological cost.
1172622
Simple... fish can breathe in water, as Oxygen is dissolved in the water already. Otherwise, its dangerous for the fish to breathe above water.\n\nn order to live, fish must extract oxygen from the water and transfer it to their bloodstream. This is done by gills, lungs, specialized chambers, or skin, any of which must be richly supplied with blood vessels in order to act as a respiratory organ. Extracting oxygen from water is more difficult and requires a greater expenditure of energy than does extracting oxygen from air. Water is a thousand times more dense (heavier per unit volume) than air, and at 20 deg C (68 deg F) it has 50 times more viscosity (resistance to flow) than air and contains only 3% as much oxygen as an equal volume of air. Fishes, therefore, have necessarily evolved very efficient systems for extracting oxygen from water; some fishes are able to extract as much as 80% of the oxygen contained in the water passing over the gills, whereas humans can extract only about 25% of the oxygen from the air taken into the lungs.\n\nGills are made efficient in a number of ways. (1) A large surface area for gaseous exchange means that more oxygen can enter the bloodstream over a given period of time. A single gill of a bony fish consists of a curved gill arch bearing a V-shaped double row of gill filaments. Each filament has many minute folds in its surface, giving it a sort of fuzzy appearance and increasing the amount of surface area along a given length of filament. Consequently, the surface area of the gills is commonly 10 to 60 times more than that of the whole body surface. (2) A short diffusion, or travel, distance for the oxygen increases the rate of oxygen entry into the blood. The blood traveling in the folds of the filaments is very close to the oxygen-containing water, being separated from it by a very thin membrane usually 1 to 3 microns (4/100,000 to 1/10,000 in) thick, and possibly less. (3) By using countercurrent circulation in the gill, the blood in the filament folds travels forward, in the opposite direction to the water flow, so that a constant imbalance is maintained between the lower amount of oxygen in the blood and the higher amount in the water, ensuring passage of oxygen to the blood. If the blood were to flow in the same direction as the water, oxygenated blood at the rear of the gills would be traveling with deoxygenated water and not only could not extract oxygen from the water but would even lose oxygen to it. (4) Gills have little physiological dead space. The folds of the filament are close enough together so that most of the water passing between them is involved in the gas-exchange process. (5) Water flows continuously in only one direction over the gills, as contrasted with the interrupted, two-way flow of air in and out of lungs of mammals.
1062365
no, because fish have gills (breathe on the outside) unlike us we have lungs in the inside.  In my aquarium tank I have a small mouth Bass & Yellow Perch, when i feed my bass minnows he would have three minnows in it's mouth (minnows literally sticking out it's mouth)/ my perch as well.  They will swim around with half a minnow sticking out it's mouth and act like it's no big deal.  You will see this with bluegill they will take the worm and swim around with it hanging out it's mouth.  I just feed my fish (thanks for reminding me) and I took pictures so if you want to see them just e-mail and I'll send it to you.  \n-About the dead smaller fish stuck in it's throat some fish I catch may puke up fish due to exhaustion.  When i go fishing for walleyes and northern pike I've had them cough up fish on me.  I've had bass do the same.  \n-Death? He could have died due to foul hooking (not meaning snagging) but if it hook in the middle or back of the throat can kill any fish especially if it's kept out of the water to long, just cut the line and release.  It doesn't work out all the time.
1184568
With the exception of lungfish, most fish don't last long out of water because they can't breathe.  They die within minutes As well, they can't move at all so they are sitting prey for predators. In hot weather, they also dry out quickly.
386053
First of all, crabs as a whole cannot survive on land.  Only a relatively few species can leave the ocean.\n\nSo, why have some crabs made it out of the water while lobsters and shrimp have not?  Body structure.\n\nShrimp are primarily swimming creatures.  Their legs are not remotely designed to support their weight.  They are not likely to evolve into terrestrial animals from their current condition.\n\nLobsters may live on the submarine ground, but they have those long tails.  Those tails would not be easily supported above the water, leaving them to drag in the dirt.  Since the lobster has rather important stuff under it's tail (including gills), this would be fatal.  They aren't going to be able to make the transition to land animal easily.\n\nCrabs were all set to evolve to life on the land just from how they evolved under water.  They lack the long dragging tail, their gills are better protected, they have strong body lifting legs.  All that's really needed is some futher modification to the gills to let them survive short jaunts on land, things easy to evolve while living near the tide lines.\n\nThere are even some crabs in the amazon that are more terrestrial than marine!
881373
The swim bladder controls the buoyancy of the animal. Normally the amount of gases in the swim bladder keeps the fish neutrally buoyant, and they can regulate these gases to go up or down in the water column.\nThis saves energy because the fish doesn't have to swim actively to stay in one place; even though their tissues are denser than water, they won't sink because the less dense gases compensate for this.
453845
Because of osmotic pressure.\n\nThe water in the fish's body is full of impurities.  You know, fish parts.  Osmosis causes water to flow automatically to less "pure" concentrations.  So, a freshwater fish has no need to drink, the water is simply pumping into it's cells.  In fact, it has to work extra hard to get waste water out of it's system so it doesn't swell up and explode!\n\nSaltwater fish have the opposite problem.  The salt in the water turns the osmotic pressure around and the oceans are constantly pumping water out of saltwater fish.  They have to drink to make up for it.
386178
Below.\nWhy?\nBecause at 100ft above water you only feel the air pressure there. While at 100ft below water, you feel both the air pressure ( strictly spreaking in physics ) plus the water pressure there.\n\nAlso, note that water is more dense than air. This means for each space, water exerts more pressure compared to air for that same displacement of space.\n\nFurther, pressure that we feel is created due to the displacement of water or air moleculs respectively by the object. So, neighbouring air/water moleculs try to "displace out" the object that caused the "imbalance" where originally there were only air/water moleculs before the placement of the object.