Over time, nitrate can start to build up in your water if it’s not removed by water changes. Brown algae loves to eat nitrate (true algaes love it, too).

How does brown algae obtain food?

Brown pigments can absorb the blue-green light energy and pass it to the green chlorophyll for photosynthesis (a process whereby algae manufacture food from carbon dioxide and water using light energy). A unique starch, laminarin is produced in brown algae.

What eats freshwater brown algae?

In a freshwater aquarium, you can add a sucker-mouth fish that will readily eat brown algae. Stock one plecostomus or several otocinclus catfish to do this job. In a saltwater aquarium, many species of fish and invertebrates are diatom grazers.