Salt Water Articles

Controlling the Growth of Algae in the Aquarium Part 2

To control the growth of algae in our tanks starting with small animals as we have seen in the previous article, which you can see here and coming to bigger animals, there is nothing left to talk about herbivorous fish.


Photo by  Felice Panico

Most Blennies do not exceed 6 inches (15 cm) in length and are a great option for algae control in reef tank.

The nice facial expression is due to the presence of fleshy lips and the broad jaw of the upper jaw, very similar to a brush, leaving traces similar to lips on diatoms, cyanobacteria, debris and filamentous algae that grow on the glass.

The Astrosalarias, Salarias, Cirripectes, Ecsenius, Entomacrodus, Istiblennius, Ophioblenius and Scartella belong to the genus Blenniidae phytophages.

The Blenniidae “Ecsenius Midas” does not feed algae but only Zooplancton. 


Many Blennies are omnivorous, but others are strictly herbivorous and suffer hunger if they do not have enough seaweed.

In these cases it may happen that they confuse coral with algae, nibbling on the Xenia or Briaerum polyps and damaging other sessile invertebrates.

It is said that Cirripectes, Ecsenius, Ophioblennius and Scartella occasionally bite the tridacne coat, perhaps to feed on zooxantelle  (Save Clam with the Glucose Method).

Photo By Felice Panico

Presumably for the same reason Ecsenius Spp. (Except E.Midas) were seen attacking hard coral tissues.

Salarias species such as Salarias Fasciata can refuse dry foods and suffer hunger in small tanks where the availability of algae runs out quickly, while in larger tanks a single individual can find enough nutrition for much longer.



One of the species of Gobids known as good herbivore is the genus Amblygobius, such as A. Phalaena, A.Rainfordi and A. Hectori, very suitable for reef tanks and easily available on the market.

These fish have a mouthpart facing down, that they use to suck sand, debris and plant filaments.

A.Phalaena is very suitable for cleaning of sandy substrates, while A. Rainfordi and A. Hectori are much more efficient in controlling filamentous algae including Derbesia. In the absence of algae, they may suffer from hunger unless they get used to eating dry commercial feed.


Photo By Felice Panico

Pomacanthidae or “Marine Angelsfish” also feed algae as well as invertebrates, sponges and corals.

Centropyge angelfish are fed with algae with a greater percentage than other Pomacanthidae, but sometimes they can damage corals and tridacne (Save Clam with the Glucose Method). They generally eat debris, diatoms, cyanobacteria and small invertebrates among plant filaments, they can also devour other types of covering algae, but not filamentous algae.


Among the fishes, the family most commonly known as algae digesters is the family of Acanthuridae commonly called “Surgeons fish” so called for the presence of a very sharp shield similar to a blade that is present in all Acanthuridae and is used as defense weapon.

Many Acanthuridae despite strong personality are very susceptible to pest infestations and need a lot of food to keep themselves healthy.

Photo By Francesco Tacchi
Photo By Felice Panico
Photo By Felice Panico







In the tank they devour very quickly all the algae available from the living furnishings and rocks, which is why it is advisable to insert only in aquariums of a minimum size of 300 liters.


The fish of the Siganidae family commonly called “Rabbit Fish” are also herbivores, capable of controlling filamentous algae and other seaweed such as bubbling algae. They can reach large sizes between 20 and 50 cm and therefore unsuitable for small tanks. In their spine they have a poison that inflicts painful injuries.


Some parrot fish such as those belonging to the Scaridae family are coral groats, but most feed on filamentous algae.

They reach large sizes if they have food available and are therefore suitable for large tanks.

The end Second Part

Follow Controlling the growth of algae in the aquarium Part 3

Controlling the growth of algae in the aquarium Part 1

Felice Panico
Acquariofilo dall'età di 10 anni con esperienza in acquariologia dolce,marina e salmastra, appassionato di immersioni subacquee e di microscopia.

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