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What causes foam on the water surface
The cause of foam formation is a high level of organic pollution in the water due to dissolved protein and cellulose compounds, e.g. B. from the fish food.
These compounds act like soap in water.
This can e.g. B. occur in newly set up and not run-in aquariums.
In such aquaria there are not yet enough microorganisms that would otherwise quickly decompose protein compounds into nitrite and further into nitrate.
Measures against foam formation
- Bring in filter sludge from another aquarium or bacterial starter
- Reduce fish stock
- Feed little, e.g. B. only every other day
- Do not clean the filter so that the bacterial cultures can multiply
- Aerate the water with an air stone or diffuser to prevent a lack of oxygen
- Check whether there is a dead fish in the aquarium
- Frequent large water changes, at least 30% every other day. This may delay the start-up of the aquarium, but prevents excessive nitrite and nitrate levels that can damage the fish.
- Alternatively: No water changes until the nitrite peak is over and there is no more foam. This may allow the aquarium to start up more quickly, but may put a strain on the fish due to increased nitrite and nitrate levels. Therefore, always monitor the nitrite and nitrate levels. Nitrite should not be detectable. Nitrate should remain below 50 mg/litre. If the values are too high, the water must be changed to protect the fish.