Cyanobacteria (cyano)
Cyanobacteria are photosynthetic organisms that form red-brown slimy mats in the aquarium. They are not algae but bacteria capable of photosynthesis.
Detailed explanation
Cyanos are among the most frustrating problems in aquarium keeping. They appear as a slimy film that covers substrate, rocks and glass. The colour varies from dark red to dark green to purple. They can be recognized because they come off in whole sheets if sucked up with the siphon. Real algae don't behave like this.
The main causes are: unbalanced nutrients (too much nitrates with low phosphates, or vice versa), poor circulation, old substrate with dead zones, excess silicates.
The detail of the nutrients is crucial. Cyanos don't appear simply because the nutrients are high. They appear when the ratio between nitrates and phosphates is unbalanced. Lowering nitrates to zero while keeping phosphates high is a perfect recipe for cyanos.
In marine aquariums, treatment with antibiotics (Chemiclean, erythromycin) works in the short term but the cyanos return if you don't resolve the cause. Better to correct the nutrient balance and improve circulation.
In freshwater aquariums, cyanos are less common but when they arrive they are just as stubborn. They often appear in aquariums with little circulation and compact substrate.
In ponds, cyano appears as a bluish-green film on the surface of the water in the warm months. The solution comes from better oxygenation and circulation.
Coralia Lab predicts the appearance of cyano with the ACD-Engine by analysing the nutrient trend before the problem becomes visible.
Coralia Lab monitors this parameter with AI diagnostics. Tank Score alerts you when a value moves outside the recommended range for your aquarium.
Try ACD-Engine (algae prediction) for free