How to Combat Derbesia in a Reef Aquarium

Derbesia is a class of green haired algae that can easily infest a reef aquarium system and run rampant if left unchecked. It is able to colonize nearly all surface areas such as live rock, sand, and corals. Fortunately, there are several effective ways to combat this nuisance algae.
1. Improve Water: Quality
Derbesia thrives in water that is rich in nutrients, such as nitrates and phosphates. For algae control, the quality of water must be kept pristine. Frequent water changes, using high-quality filtration media and test for the levels of nutrients can be used to achieve this.

2. Increase Lighting:
Derbesia grows well under low light, therefore its light can be manipulated for its growth. Yet it is also worth mentioning that simply increasing the light may not be sufficient to wipe out Derbesia completely. .

3. Add Algae-Eating Invertebrates:
Several species of invertebrates (including snails, hermit crabs and sea urchins) enjoy feeding on Derbesia. Incorporating a cocktail of these animals into the aquarium may be able to control the algae growth.

– Yellow tang (Zebrasoma flavescens)
– Sailfin tang (Zebrasoma veliferum)
– Powder blue tang (Acanthurus leucosternon)
– Naso tang (Naso lituratus)
– Rabbitfish (Siganus spp.)
– Sea urchins (various species)
– Turbo snails (Turbo spp.)


It’s important to note that not all of these species are compatible with each other or suitable for every aquarium, so it’s important to research and plan carefully before adding any new livestock to your tank. More specifically, although these same species have been documented to graze on Derbesia algae, they may not be sufficient to clear an outbreak on their own and in such a case would, likely, benefit from other management techniques such as manual removal or chemical treatments.
4. Use Chemical Treatments:
Battre Darbesia is several chemical treatments at hand that may be effective against it. However, it is important to use these treatments with caution, as they can harm beneficial organisms in the aquarium if used improperly. Always follow the manufacturer’s instructions as it is written carefully, and closely observe the aquarium after treatment” (p. 2).
Here are some chemical treatments that can be used to control Derbesia algae in a reef tank:
1. Hydrogen peroxide: This is a common treatment for Derbesia algae. It can be directly applied to lesioned regions using a syringe, or dropper. The recommended concentration of hydrogen peroxide is 3 ml for 10 US gallons of water, however, it should be noted that the initial dose of hydrogen peroxide in the tank should not be higher than 3 ml per 10 US gallons and the tank’s condition should be strictly monitored for any toxic reaction.

2. AlgaeFix: This is a commercial product containing a cocktail of active substances which act against different algae categories, such as Derbesia. Carefully comply with dosage instructions and observe the tank carefully for any side effect.

3. Vibrant: This is a commercial product comprising a mixture of bacteria and other natural constituents which are specific to different species of algae, Derbesia. It is crucial to adhere strictly to the dosage protocol and to attentively observe the tank for any toxicity.


It’s important to note that chemical treatments should be used as a last resort and only after other management strategies, such as manual removal and controlling nutrient levels, have been attempted. Also, before next using chemical treatments, it is necessary to eliminate dead algae, and to do water changes in order to avoid any possible negative impact on the water quality of the tank.

5. Manual Removal:
Specifically, the manual algal removal is an efficient means to control Derbesia. This may be accomplished by use of a toothbrush or small brush to remove the algae from aquarium surfaces1. Be sure to remove as much of the algae as possible, as even a small amount can quickly regrow.

Derbesia can be a maddening issue for reef aquarium keeps, but it is not a lost cause. Through keeping the water clear, decreasing the light, introducing light-eating invertebrates, minimal use of chemical dissolving agents practiced with discretion, and hand removing the algae it is possible to defeat Derbesia and keep a healthy and thriving reef aquarium.

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