Dear all, I am currently experimenting Tilapia in a biofloc system. After rearing the juveniles for few weeks, the water in my tanks started to have a lot of brownish foams. These foams begin to cover the water surface, obstructing my observation and causes fish mortality daily due to DO deficiencies . I measured the water quality parameters (TAN, nitrite and nitrate,pH,temperature, TDS ) and those are within the optimum range. I have read about possibility of biofloc transition that will cause the large amount of forming.
But what are the possible reasons that will cause the large foaming like this? Is it bad if it continues to bloom? Any alternative methods to reduce it?
In my experience, that is usually caused by a high amount of proteins within the water column. This is caused by the biofloc itself, uneaten food particles and fish waste. What's your filtration like? Do you have a protein skimmer and mechanical filtration implemented into your fish system?
Dear Md. Atique Ashab ,
For immediate action to reduce the mortality, you can reduce the bacterial load by water exchange with new water with the same parameters. Then slowly adjust the feeding and then develop the biofloc in the culture water.
Hope it will help.
Most ponds with a waterfall or fountain have some foam or froth from normal water agitation. But if that foam keeps accumulating and does not dissipate, spreading like a white carpet across your pond, it may be a sign of an underlying problem with your pond's water conditions. These stubborn bubbles (white foam) are commonly due to an excess of dissolved organic compounds (DOCs) collecting in a slick along the water's surface. The DOCs can come from many sources including overfeeding, a buildup of fish waste, or decaying plant material. DOCs not only produce unsightly foam, the can also reach a level at which they become deadly to your fish.
Use a test kit to check for ammonia, nitrite, and nitrate levels. Trace amounts of nitrate are acceptable, but if any ammonia or nitrite are present, your pond may not be cycled correctly and is out of balance. In other words, there is more waste being produced than can be processed by the bacteria and plant life available. Your pond may need more biological filtration or bacterial additives to bring conditions back into balance.
High nitrate can mean that you have an overstocked pond or you have not performed a water change for a long time. If water changes are performed regularly, you have 2 choices: reduce your fish population, or reduce the amount of DOCs your filter must process. Reducing the amount of DOCs can be approached in several ways:
If your filter is not adequately sized for your pond's volume, DOCs may be collecting on the water surface. To remedy this situation you will need to either add another filter, or get a larger one; remember it's always safer to use a larger filter than recommended by the manufacturer.
The same solutions you may use during routine water changes to make your tap water safe for your pond fish can also cause foam buildup. If this is bothersome, try a water purifier system especially made for ponds such as the PondFil Float made by Kent Marine. This connects to your outdoor faucet/garden hose and automatically adds filtered water back into your pond when it drops below a certain level due to evaporation or normal water changes.
Medications can also cause a waterfall or fountain to foam, although is should dissipate within a day. Since you will need to remove any chemical media such as carbon for treatment, and any foam covered surface area cannot efficiently exchange oxygen, it would be wise to run an aerator during treatment. If possible, it is more productive, safer, and cheaper to treat diseases by removing the fish to a separate container.
A great solution, regardless of the cause…A main way of controlling the buildup of DOCs in the average garden pond, regardless of the cause, is to increase the number of water changes. In some geographical areas and in very large ponds, the cost and/or amount of water needed may be unfeasable. In these situations, a foam fractionater or protein skimmer may be helpful. Ironically, a protein skimmer actually uses bubbles to attract protein molecules. The resulting foam is then removed through a disposal hose.
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