Dinoflagellate growth

Dinoflagellate Alga

Note: Another type of problematic slime-like brown alga is caused by a dinoflagellate. It can result in large areas, including the surfaces of invertebrates, being coated in a brown gelatinous mass. It is usually introduced on a new piece of live rock or coral animal and can easily become problematic if the bulk water is rich in organic material.

This free-swimming alga is extremely difficult to cure. Silicate is not one of its needs as is the case with diatoms. Unfortunately calcium carbonate is. Bear in mind a small microscope would help identify which form of brown algae is in the aquarium. If the alga cell has a flagellum, i.e., a tail (for propelling itself through water), it is a dinoflagellate. It can be reduced/eliminated with the use of ozone or a UV sterilizer. Also, flowing all aquarium water through a sponge filter, which should be cleaned twice a week, is also helpful. And if a quality brand protein skimmer is not being used, it should be as this pest does best in high organic conditions.