Undesirable Water Conditions: Cause and Prevention
June 16, 2011
Green Water
An outdoor pond will never be totally free of algae, nor should it be. Algae serves as a source of food for many micro organisms and is a critical part of the food chain.
Green water is caused by single-celled free-swimming algae. They are individually microscopic but may be present in such numbers as to make the pond appear as though it were filled with pea soup. Their existence depends on the presence of light and nutrients (primarily phosphate and nitrate) both of which are abundantly available in a newly filled pond in which plant growth is still relatively undeveloped. As the pond plants mature they will provide shade for the water and begin to absorb the dissolved nutrients required for the algae to survive. The algae begins to die and sinks to the bottom where it is eaten by the fish. The water clears, and it very often happens abruptly. There is no “normal” period for this; it depends on many variables… water chemistry, plant density, livestock levels, seasonal weather… that are different for every pond. Water changes will not accelerate the process. They may alleviate the problem temporarily, but in reality the newly added water is rich in nutrients which merely serve to start the cycle again. Plants and patience are the answer to most green water problems.
Brown Water
Murky brown water is the result of muddy sediment being stirred up by fish or by water turbulence. It may have a greenish cast because such stirring tends to encourage algae growth. The sediment must be allowed to settle and then be siphoned off or removed by filtration.
Milky Water
Milky, clouded water indicates decay and water pollution. It is caused by the decomposition of organic matter, particularly of fleshy origin. Change the water and search for the source of the problem; usually a decomposing fish.
These Topics are on misc. topics but most helpful when needed.
June 16, 2011
Diseases
Well-nourished fish in a well-managed pond have a strong natural resistance to the potentially harmful organisms that always surround them. Continuing health depends more than anything else on keeping the water free from pollution in the form of organic debris. The water may look perfect but still be lethal. That is why a water change is often a necessary part of the treatment of disease problems.
The fish can only symptomatically inform us of the nature of its malady. Consequently diagnosis must depend on intelligent observation of the owner, particularly of behavior and appearance before death. Water quality values (pH, ammonia, nitrite, nitrate and dissolved oxygen) must be known quantities before a diagnosis can even be attempted. If the problem is a result of poor water quality, medication will serve no purpose whatsoever. The systematic use of test kits is a mandatory part of pond keeping.
Parasites
Parasites are the most common pond fish ailment and are usually of the ecto-parasite variety… that is, living on the outside of the fish. They may enter your pond from bird droppings, occur in live foods, or even be introduced from a fish purchased from The Aquatic Critter, though we make every effort to insure otherwise.
Symptoms of parasitic infestation include clamped fins, listlessness, poor appetite, excess mucous secretion and/or rubbing (flashing) against the bottom or sides of the pond. Parasites affecting the gills will generally cause symptoms of rapid gill movement or gasping at the surface. It is generally the weakest fish in the pond or one with a damaged mucous coating that becomes the host.
Fungus
Fungus spores are present in all water; fish are surrounded by them all their lives. As long as the fish are well nourished, undamaged, and living in well oxygenated, unpolluted water their resistance to infection is complete. Fungus infection is always a secondary problem and a clear indication that there is something else amiss. In addition to treating the fish, it is vitally important to discover and correct the conditions that made the fish susceptible to infection.
Fungus is not infectious from fish to fish. However, if a number of fish share the same unhealthy situation it is likely they will all develop fungus; but they will not have caught it from each other.
Fungus, which destroys the area to which it is attached, appears on fish as a white cotton, wool-like growth on the skin, fins, or gills. It’s commonly known as “cotton-wool” disease.
Bacterial Infection
The buildup of bacteria that can affect pond fish is generally caused by poor water conditions due to the accumulation of organic debris. Medication may provide temporary arrest of the infection but the condition is likely to reoccur if the underlying cause is not corrected by at least a partial water change.
Symptoms may include clamped fins, listlessness, poor appetite, fin and tail deterioration, cloudy eyes, body film, blood red streaks in the fins and tail, and bloody patches on the skin.
Dropsy
There are many suspected causes of this disease, but the primary causative is thought to be poor water quality. The most noticeable symptom is the protrusion of the scales away from the body, giving a “pine cone” appearance. The disease severely affects all of the internal organs and medication rarely provides long term benefits. The best course of treatment is to destroy the infected fish. The disease is not thought to be infectious from fish to fish.
Unexplained Fish Death
When the process is gradual, fish being lost at intervals, one or two at a time over a period of time, there must be a strong suspicion that they are suffering either from some form of water pollution or from flukes (parasites). All the possible causes of pollution should be considered and any necessary steps taken to correct them. The most common are too many fish, overfeeding and too much decaying debris. In all cases where pollution seems a plausible explanation, a water change is called for.
The sudden death of a number of fish which had seemed to be in good health can only be explained in terms of some very drastic form of pollution rather than disease. The only action possible is a complete water change.
