Janitor fish, anyone?

Here are bits of information about the "janitor fish" to enlighten the people, particularly those around Laguna Lake and Marikina River, who have been alarmed by the proliferation of this species in the two bodies of water.

The "invasive" fish species, an introduced aquarium catfish from South America that has escaped into Laguna Lake and Marikina River, is a "nuisance" fish.

But now comes the Los Baños-based Department of Aquatic and Marine Research and Development (PCAMRD), through Executive Director Rafael D. Guerrero III, issuing updates on the "janitor" fish.

PCAMRD said that there are two species of the fish that have been correctly identified by Edna Agasen, senior fishery biologist of the DA-National Fisheries Research and Development Institute with the assistance of Dr. Jonathan Armbruster, curator of fishes at the Auburn University in the United States

The species are Pterygoplichthys parotalis (found in Marikina River and Lake Paitan Cuyapo, Nueva Ecija) and Pterygoplichthys disjunctivus.

"This report now corrects the former identification of the ‘janitor fish,’ Plecostomus hypoglosus, in the country," Dr. Guerrero said.

Dr. Armbruster added that the fish is eaten by South Americans.

Does the janitor fish threaten native and cultured fishes?

"The fish builds its nests in mud banks and can contribute to water turbidity," Dr. Armbruster said. They may compete with other fishes breeding on algae and detritus (organic matter) in the bottom. In its natural habitat, if feeds on tadpoles and insects.

Since janitor fish breeds and grows quickly, it is suggested that the best way to reduce its population is by catching the adults. – RAF