Activated carbon is commonly used as a filtration media in aquariums due to its excellent adsorption properties. It helps to maintain water quality by removing impurities, odors, and discoloration from the aquarium water.

Activated carbon has a porous structure with a large surface area, allowing it to adsorb various chemicals and compounds present in the water. It can effectively remove toxins, heavy metals, chlorine, chloramines, and other harmful substances that might be introduced into the aquarium water.

Sometimes, aquarium water can become cloudy or discolored due to organic compounds, tannins from driftwood, or other dissolved substances. Activated carbon can help clear the water by adsorbing these color-causing molecules, resulting in clearer and more visually appealing water.

In some aquariums, especially those with high biological activity, unpleasant odors can develop due to the breakdown of organic matter. Activated carbon can adsorb these odor-causing compounds, improving the overall smell of the aquarium environment.

When treating fish for diseases using medications or chemicals, residual substances can remain in the water even after the treatment is complete. Activated carbon can aid in removing these residual chemicals, preventing them from negatively affecting the fish or other aquatic life.

Activated carbon can help reduce the accumulation of organic waste and dissolved organic compounds, thereby contributing to the overall reduction of organic load in the aquarium.

While activated carbon is not a replacement for biological filtration, it can help prevent sudden spikes in ammonia levels by adsorbing certain organic compounds that contribute to ammonia production.