Issue qt fish HELP

[LOVEROCK]

Would fin damage be a result of ammonia ? And what levels of ammonia will be lethal ?

 

[MnFish1]

Would fin damage be a result of ammonia ? And what levels of ammonia will be lethal ?

It can - the lethal level depends on the fish. Best to shoot for 'zero'.

From article:

Toxicity of Ammonia

Ammonia is very toxic to marine fish. The mechanisms of toxicity are complicated and are an active area of continued investigation by researchers. Its effects include damage to the gills, resulting in poor gas exchange, ion regulation and blood pH regulation.14 Other effects include hampering oxygen delivery to tissues, disrupting metabolism and toxicity to the nervous system that causes hyperactivity, convulsions and death.14 Ammonia can also be very toxic to many other organisms found in reef aquaria.

Toxicity can be measured and reported in many ways. One common way to measure acute toxicity is to measure how high the concentration needs to be in order to kill half of the organisms in a given time period. A commonly used time period is 96 hours (four days). Such data are called the 96 h LC50 (LC stands for Lethal Concentration, 50 meaning 50% killed).

The other complication that comes with ammonia's toxicity is the relative amount of free ammonia and ammonium ion. While ammonium ion may be toxic to marine fish, it is probably less toxic than free ammonia, and toxicity data are often reported only for the concentration of free ammonia. Aquarists should recognize, however, that such data may not be appropriate if the pH used in the test, or the situation to which it will be applied, deviates significantly from normal seawater's pH (as in a shipping bag, for example, whose pH may be well below pH 8.2, and whose toxicity may actually be coming from ammonium, and not the low concentration of free ammonia). Nevertheless, many scientific articles report ammonia toxicity in ppm (or mg/L) NH3-N. It may also be reported as just ppm NH3.

Marine fish14 generally have 96 h LC50 levels that range from about 0.09 to 3.35 ppm NH3-N. That result is not particularly different from the range observed for freshwater fish,14 0.068 to 2.0 ppm NH3-N. Remember that these values are ppm NH3-N, and at pH 8.2, the marine range becomes 1.3 to 50 ppm total NH4-N because only 7% of the total ammonia in seawater is present as free ammonia.

Concentrations of ammonia that are not acutely lethal can still cause significant problems for fish. Salmon in seawater at pH 7.8, for example, show changes in white blood cells and various blood chemicals, and were more prone to disease, when exposed to sublethal concentrations of ammonia.15Consequently, aquarists should strive to keep ammonia concentrations well below lethal levels.

Ammonia Concentration Guidelines

Because ammonia's toxic effects appear at levels significantly below those that are acutely lethal (0.09 to 3.35 ppm NH3-N or 1.3 to 50 ppm total NH4-N at pH 8.2), and because some organisms in a reef aquarium may be more sensitive than the few organisms that have been carefully studied, it is prudent to err on the side of caution when deciding what concentrations of ammonia to allow in a reef aquarium or related system.

My suggestion is to take some sort of corrective action if the total ammonia rises above 0.1 ppm. This suggestion is also made by Stephen Spotte in his authoritative text, Captive Seawater Fishes.6 Values in excess of 0.25 ppm total ammonia may require immediate treatment, preferably involving removal of all delicate (ammonia sensitive) organisms from the water containing the ammonia. Some of the possible actions to take are detailed in the following sections listed below.