My tank has ich! :( - Page 2 - Tropical Fish Keeping - Aquarium fish care and resources
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post #11 of 12 Old 09-11-2010, 11:24 AM
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Nor is that high temp healthy for many fish, such as Denison Barbs. I'm not sure how shortened their life spans would be subjected to such heat but I would think it would knock quite a few years off of their lives. I would suspect that kind of heat would negatively impact the lives of many of the fish we keep. Here's some interesting info from a post by Byron:

"Salt is detrimental to freshwater fish and plants in varying degrees. To understand why, we must understand what salt does in water.

Salt makes the water more dense than the same water without salt. The aquarium contains water. The bodies of fish and plant leaves also contain water [just as we do--we are, what is it, 90-some percent water?]. The water in the aquarium and the water in the fish/plant are separated by a semi-permeable layer which is the cell. Water can pass through this cell. When either body of water is more dense, the other less-dense body of water will pass through the membrane to equalize the water on both sides.

Water is constantly passing through the cells of fish by osmosis in an attempt to equate the water inside the fish (which is more dense) with the water in the aquarium. Put another way, the aquarium water is diluting the fish's body water until they are equal. Freshwater fish regularly excrete this water through respiration and urination. This is the issue behind pH differences as well as salt and other substances. It increases the fish's work--the kidney is used in the case of salt--which also increases the fish's stress in order to maintain their internal stability. Also, the fish tends to produce more mucus especially in the gills; the reason now seems to be due to the irritant property of salt--the fish is trying to get away from it.

I have an interesting measurement for fish. Dr. Stanley Weitzman, who is Emeritus Research Scientist at the Department of Ichthyology of the Smithsonian Institute in Washington and an acknowledged authority on characoid fishes, writes that 100 ppm of salt is the maximum for characins, and there are several species that show considerable stress leading to death at 60 ppm. 100 ppm is equal to .38 of one gram of salt per gallon of water. One level teaspoon holds six grams of salt, so 1 tsp of salt per gallon equates to more than 15 times the tolerable amount. Livebearers have a higher tolerance (mollies sometimes exist in brackish water) so the salt may be safe for them.

Plants: when salt is added to the aquarium water, the water inside the plant cells is less dense so it escapes through the cells. The result is that the plant literally dries out, and will wilt. I've so far been unable to find a measurement of how much salt will be detrimental to plants; all authorities I have found do note that some species are more sensitive than others, and all recommend no salt in planted aquaria.

Now you know why I never recommend salt."

If you don't stand up for something you'll fall for anything...

Last edited by aunt kymmie; 09-11-2010 at 11:27 AM.
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post #12 of 12 Old 09-12-2010, 04:26 PM
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I definately don't want to get into an argument about this but I've seen studies that contradict Byron's post with actual numbers and data not just some "Recognized Expert's" writings. I have also seen fish including amazonian catfish and tetra tolerate 3 tablespoons of salt per gallon for over 3 weeks while medicating and by the math in the post this is nearly 100 times the fatal level. Also on the subject of osmosis, fish naturally maintain a specific gravity higher than the fresh water they are in. Until you exceed this level there is no osmotic pressure. Also read your ich medicine's botlle many commercially prepared ich treatments contain in addition to copper, malachite green, or some other toxic heavy metal, SALT. Also I am from Florida and I have been in fresh water that was in the 90 degree range and all the fish weren't floating belly up. Like I said in my original post I do not reccomend salt for general purpose use in a fresh water aquarium and would lower the dosage to 1-2 tablespoons per gallon for tetra and loaches but, it is an effective disease treatment that is used by veterinarians, commercial fisheries, and government agencies and has been for over a century. I just don't want newcomers to the trade gettting scared away from one of the most effective and proven disease treatments for freshwater fish when I have seen the numbers that prove its effectiveness and witnessed the results myself.
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