why do fishes produce bubbles?
367578
because they give out carbondioxide
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.
704415
Sounds like your fish has what is called ick. Here's is a site that you can get more information about it.
29645
It probably is evaporating from the top. The bubbles on bottom are just more visible.
1021680
Depends on the kind of fish!\n\nTrouts need an extreme amount of oxygen, while some other fish could do with 10% of the amount...
184692
Fishes have eyeballs, two of them in their optic capsules, just like all other vertebrates. They're surrounded partly by bone, and partly by an elastic but resistant capsule. \nBony fishes don't have eyelids, but sharks and rays do\n(see answer at \nhttp://answers.yahoo.com/question/index;_ylt=AqPoH8mhQReCU_CYDM1Fvirsy6IX?qid=1006030500996 )\n\nAnd they _do_ have nostrils, but, as you have rightly deducted, they're not used for breathing. \nIf you look at a bony fish (a goldfish or whatever you have at hand) you'll see that it has TWO nostrils on each side of its snout (they can be close together or really distant). Between these two nostrils of each side there is a tube with special olfactory (smelling) cells, like the ones we have in our own noses. The water with chemical "smell/flavor" molecules goes in through the anterior opening, and flows out through the posterior opening. Thus, fish nostrils (derived from the primitive pair of olfactory capsules) are used for smell/flavor perception, and not for breathing (which occurs at the gills). \nIt's only in tetrapods (from amphibians to reptiles, birds and mammals) that the connection between the nostrils and the respiratory system occurs (and the lungs appear). If you open a frog's mouth (please only try it with a dead animal!) you'll see two paired holes in the roof of its mouth. Those are the internal nostrils (called "choanae") and they allow passage of breathing air to the mouth--> pharynx--> lungs. \n\nAdditional trivia:\n- Our own internal nostrils open way back in our pharynx, because we have a secondary palate.\n- Cartilaginous fishes have only one nostril on each side of the snout. However, each nostril is partly separated into 2 parts by a flap of skin, and actually water flows through the nostril just as in bony fishes.\n- Some bony fishes, the cichlids (discus, Jack Dempsey), have only one nostril on each side of the snout.
628752
Unlike marine mammals such as whales and dolphins with lungs that store oxygen from the surface air, fishes have gills. Gills are a series of membranes located on each side of the fish that function as respiratory organs. As water passes over this system of extremely fine gill membranes, the fishes absorb the oxygen from the water. The gills contain a network of fine blood vessels (capillaries) that take up the oxygen and diffuse it through the membranes. When fishes are taken out of water, they suffocate, because their gills collapse and they are unable to absorb oxygen.In many ways, the interior of the fish resembles that of many other animals. The digestive, circulatory, and nervous systems are very similar to those of other vertebrates. However, what really makes a fish different from other animals is its respiratory system. \n\n\n\nA fish’s respiratory system is determined primarily by the fact that it spends its entire life in water. Unlike the marine mammals such as whales, a fish has evolved in such a way as to not require frequent trips to the surface to breathe air. Fish have developed gills, on which they rely for the oxygen necessary for a fish’s limited metabolism. \n\nMany animals have gills at some stage of their life (even humans have them at an early stage of their development in the womb), but fish retained these gills and they are still a functional part of their anatomy. Fish use their gills to extract oxygen from their watery environment. The process starts with the fish’s mouth, which is how the fish takes in water. When a fish opens and closes its mouth, it is actually pumping water back through the gills and is thus breathing. Most fish have an effective pumping system that involves the mouth and the outer cover of the gills, called the operculum. When the fish’s mouth opens, the operculum closes, drawing water into the fish’s mouth. When the fish closes its mouth, the operculum opens, allowing fresh water to cross the gills. Other fish have a less effective pumping system, requiring them to swim constantly to keep fresh, oxygenated water flowing over the gills. These types of fish, such as tuna, generally swim with their mouths partly open. Incidentally, while many fish have nostrils, the nostrils are used only for a sense of smell, and play no part in respiration. \n\nOnce through the mouth, the water continues past structures called gill rakers. The gill rakers are essentially a filter system for the gills, straining the water to sift out floating food particles or foreign material. After passing through the gill rakers, the water continues through the gill arches and actually passes over the gills, which are suspended between the mouth cavity and the operculum. Each gill is made of two rows of gill filaments, which are extremely thin membranes sticking out into the water flow. Each of the gill filaments is composed of rows upon rows of lamellae, which are thin, disc-like membranes loaded with a capillary network. The water flows across the lamellae, and oxygen and carbon dioxide are exchanged directly across the capillary membrane. The capillaries are situated to take best advantage of the water flow; fish can actually extract up to 85% of available oxygen out of the water. Since water contains only 2-5% of the available oxygen that air at sea level does, such a high efficiency is extremely important. \n\nFrom the gills, the deoxygenated water passes out the operculum, and the oxygenated blood joins the circulatory system. Despite the efficiency, some fish require more oxygen than others. This helps to explain why some fish thrive in specific habitats. For example, trout prefer northern streams because the cool water of the streams tends to retain dissolved oxygen, and the active trout need the extra oxygen. Carp, on the other hand, are sluggish and do not need as much oxygen, which is why carp can thrive in warm, relatively stagnant ponds, such as ornamental ponds. Goldfish, unlike most f
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There is no single mechanical form or chemical reaction to properly describe the process that fish gills use to remove oxygen from the water and get it into their blood system.\n\nThe site below is the single best resource to cover this topic:
460243
i assume you mean why dont the rotten eggs "drown" as in sink. well this is because when they go rotten as the egg starts to decay it broduces gas, mostly methane and sulphor so this means thats the egg becomes lighter so making it float.
411135
I think, and my marine physiology is rather out of date, that if a swim bladder was so packed with air that it would be unable to hold any more, the fish would be forced to the surface because of increased buoyancy, unless it expended a huge amount of energy to counter that (think 'swim down' from Finding Nemo, but have them doing it all the time).  If the swim bladder was unable to take in any air at all, and was somehow kept empty, the perch would sink unless it made the effort to keep itself at a certain depth.
686922
The water from the bottom is being transformed from liquid to gas and the gas bubbles to the top.  Kinda like when you're in the bathtub and fart.
514779
it all has to do with pressure, the internal pressure of a fish matches the pressure of the surrounding sea, in other words, they are of equal pressures, more or less
912906
bubles are formed because the air trapped b/w  the layers of water molecules surface out.due to surface tension of water, a thin film of water traps this water. that's how bubles are formed.
22783
The bubbles are not "air" as most of the other answers claim; they are gaseous water, otherwise known as steam.  reverie's assertion about water pressure is also incorrect.  In a pot, the bubbles primarily form at the bottom of the pan because that's the hottest part of the pan and water.  The water there gets above the boiling point (212 F) and changes to steam.  At first, surface tension keeps the bubble stuck to the pan. But when enough steam is generated to make the bubble large enough, the bouancy of the bubble forces it to rise to the surface.
674848
It could be that lol or it may be due to the bacteria that lives within the body of water, such as blue algae. :)
1013125
im assuming you mean bubbles in a drink, not soap bubbles in the air,.\n\nthese are affected by drag and hydrostatic forces.\n\nas the bubble (which has a flexible form) moves upwards through the water, the outer skin of the bubble interacts with the water. this drag causes the bubble to be slightly pulled in one way or another. this slightly deforms the bubble, and this causes its direction to change.
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Fish can often be seen gulping air from the surface during heat waves when oxygen in the water is depleted, other fish eat from the surface