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Disease Name: Saprolegnia
Additional Names: True Fungus, Water Mold
General Information:
If you've ever seen uneaten fish food in your tank covered in white, cottony stuff, you've seen Saprolegnia in action.
Saprolegnia is not often seen on live fish. It normally grows on dead or dying organic matter. Dead fish eggs are a perfect medium for the growth of saprolegnia. Having said that, it is possible for damage to the skin, fins or gills to lead to a secondary invasion by the saprolegnia. In this case, an underlying bacterial infection should be identified and treated (in addition to the fungus) in order to control the spread of the fungus.
Saprolegnia is also known as a 'cold water' fungus, as it is more prolific in cooler water.
Between 32F and 41F - Minimal growth
Between 41F and 59F - very slow growth
Between 59F and 86F - optimum growth
Between 83F and 95F - Minimal growth
Diagnostic PointersSaprolegnia is not often seen on live fish. It normally grows on dead or dying organic matter. Dead fish eggs are a perfect medium for the growth of saprolegnia. Having said that, it is possible for damage to the skin, fins or gills to lead to a secondary invasion by the saprolegnia. In this case, an underlying bacterial infection should be identified and treated (in addition to the fungus) in order to control the spread of the fungus.
Saprolegnia is also known as a 'cold water' fungus, as it is more prolific in cooler water.
Between 32F and 41F - Minimal growth
Between 41F and 59F - very slow growth
Between 59F and 86F - optimum growth
Between 83F and 95F - Minimal growth
Cotton-like white to gray-white or gray-brown growth on fish or on dead fish eggs.
* Should not be confused with excess mucus which is often described as a 'fungus'. Take care to treat for the appropriate ailment.
Using a microscope at low magnification, you can see the strands that make up the fungus.
Treatment* Should not be confused with excess mucus which is often described as a 'fungus'. Take care to treat for the appropriate ailment.
Using a microscope at low magnification, you can see the strands that make up the fungus.
Malachite Green is the #1 treatment to combat Saprolegnia. Salt is also effective against Saprolegnia. Both treatments can be given in either a bath or a dip.
Malachite Green Bath: use 0.5 ml per gallon for one hour.
Malachite Green Dip: use 30 ml per gallon for 1 minute.
If you decide to use the Bath or Dip methods, NEVER leave your fish alone during the treatment. You want to be able to remove the fish from the medication if you see any signs of stress. No one wants to go get a cup of coffee and come back to a dead or dying fish.
Maroxy by Mardel is also an effective medication to treat this fungus. However, in my experience, it is not the best for extreme cases.
As with all treatments, please read the labels carefully, follow the instructions for dosage explicitly, and know what your fish can tolerate. Some fish can not handle any amount of salt and are sensitive to certain medications.
Malachite Green Bath: use 0.5 ml per gallon for one hour.
Malachite Green Dip: use 30 ml per gallon for 1 minute.
If you decide to use the Bath or Dip methods, NEVER leave your fish alone during the treatment. You want to be able to remove the fish from the medication if you see any signs of stress. No one wants to go get a cup of coffee and come back to a dead or dying fish.
Maroxy by Mardel is also an effective medication to treat this fungus. However, in my experience, it is not the best for extreme cases.
As with all treatments, please read the labels carefully, follow the instructions for dosage explicitly, and know what your fish can tolerate. Some fish can not handle any amount of salt and are sensitive to certain medications.