Quick SW question!
- Thread starter Dr.Gonzo
- Start date
To keep it simple (because I am not a scientist and can't explain it as such) I believe it has to do with Osmosis......namely Osmotic Pressure. A fish is adapted to a certain sality (such as a salt water fish) and when placed in a dramaticaly different salinty their cells can basically.............burst. A salt water fish placed in FW will die very quickly. Hope that helps, someone else may be able to explain it better.
SW fish are adapted to live in the higher salinity of SW, in that they conserve water in their bodies and expel the salt at a much higher rate than FW fish... FW fish pee a lot of weak urine to conserve their salt, and SW fish pee only a little of very highly concentrated (salty) urine to conserve their water.
This is from Aquarium Fish by Dick Mills:
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Osmosis
A fish's skin acts as a semipermeable membrane, or a one-way transfer systemfor water. Osmosis causes fluid to diffuse through this membrane until there is an equal concentration on both sides of the membrane. The fluid of a freshwater fish's body is more concentrated than the liquid in which it lives. Thus, water costantly passes into the fish. To avoid bursting, freshwater fihes excrete as much water as possible and drink little. Conversely, Marine fish lose water to more concentrated sea water outside, and must drink constante, but excrete little.
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Osmosis
A fish's skin acts as a semipermeable membrane, or a one-way transfer systemfor water. Osmosis causes fluid to diffuse through this membrane until there is an equal concentration on both sides of the membrane. The fluid of a freshwater fish's body is more concentrated than the liquid in which it lives. Thus, water costantly passes into the fish. To avoid bursting, freshwater fihes excrete as much water as possible and drink little. Conversely, Marine fish lose water to more concentrated sea water outside, and must drink constante, but excrete little.
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okay if your really curious abouyt this stuff i have the all out best resource for you...
Google
wow, arent i the smashing genuis...
-Java
wow, arent i the smashing genuis...
-Java
live bearers can be adapted to higher salinities, and some actually like it. i know mollies like a little salt. salt water fish just need the salt because thats what they have always lived in. its why true africans have dark skin. living near the equator with year round intense sunlight caused them to produce more melanin in their skin giving them darker color, and greater resistance to skin cancer. it would belike a fair skinned person (fresh water fish) moving to africa (the ocean) and being exposed to sun (salt) 24/7. the results wouldnt be good. plus, the fish's respiratory system might not be able to handle it. there is less oxygen present the higher the salinity.
actually Twingine is what i use, a combination of the two.
but gonzo asked a question that has had many articles written about it so i persived it as pure laziness on his part
cheers
-Java
but gonzo asked a question that has had many articles written about it so i persived it as pure laziness on his part
cheers
-Java
I thought it a decent question. Google is far better suited to questions like 'I bought skimmer x, is it a heap of rubbish'.
FWIW mollies have a lot of phsiological 'setup' that is more similar to marine fish than freshwater fish i.e. the gill rakers , which fish use to excrete water and urine are marine in style. That is why they do better in very hard or brackish water but faile to thrive in very soft water. Some, but not all mollies adapt perfectly well to full strengh seawater.
FWIW mollies have a lot of phsiological 'setup' that is more similar to marine fish than freshwater fish i.e. the gill rakers , which fish use to excrete water and urine are marine in style. That is why they do better in very hard or brackish water but faile to thrive in very soft water. Some, but not all mollies adapt perfectly well to full strengh seawater.