Wednesday, October 17, 2007

Possible Solutions to the Janitor Fish Problem

JANITOR FISH (Pterygoplichthys disjunctivus- Laguna de Bay, Pterygoplichthys pardalis- Marikina River, Lake Paitan in Cuyapo, Nueva Ecija)

That cute aquarium cleaner that we love has now turned into a serious menace. It bores holes in the mud that results to water turbidity and the destruction of the river banks. Fisher folks at the Laguna de Bay claim that the janitor fish now comprise 75% of the fishermen’s daily catch. Though very alarming, the figure hardly surprises me. Janitor fish eats like there’s no tomorrow and rapidly increases in population. It largely feeds on algae and pollutants which the Laguna lake has a lot in stock.

The problem is, with its population becoming so hugely disproportional to the rest of the lake's aquamarine life, it started to compete with other fishes for food. And with food becoming scarce, I really won’t be surprised if it will not start feeding on small creatures. The last report states that janitor fish weighing as much 30 kgs a piece is now a common catch at the Laguna lake. And what type of food fish at the Laguna lake weighs lower than that? May I enumerate the following: Bangus (Milk fish), Tilapia (St Peter’s fish), catfish, mudfish, carp… everything!!!

Now that we are in agreement that the janitor fish is a big threat to the 28,000 fishing families (along the Laguna de Bay) and the consumers within the National Capital Region, let’s help eradicate these pests.

Here are the known alternative uses of Janitor Fish:
  1. Its skin can be converted into wallets, purses, watch straps, billfold and key chains using skin from the belly of the fish. Creating other fashion items out the skin should not be so difficult.
  2. The fish can be processed into chicken and pig food.
  3. In an experiment, High School kids from Marikina were able to produce half a kilo of Biofuel for every 12 kilos of Janitor fish.
  4. The government, through foreign donors pays Php 10 for every kilo of that dreaded fish.
  5. Your suggestion please....

Please add your ideas to this list.

Maraming salamat!


Anonymous said...

Janitor fish was found to contain heavy metals... so it may not be safe to be eaten by animals or humans! by biomagnification, if it is used as feeds, it will just end up in humans. Most of the heavy metals are found in non-edible parts of the fishes, most likely same is true with Janitor fish-- so maybe if we really are hungry, we can eat the edible part (which is the flesh?) of this ugly fish-- but definitely not as feeds--

jc smith said...

Thanks for the comment. It's very informative. By the way, as feeds, maybe we can do the same process and strip the ugly fish of its non edible parts and grind the rest and convert it to feeds. -- just wondering!

Anonymous said...

I don't think it's a best idea to convert janitor fish into feeds. In the Agusan Marsh (one of the most ecologically significant wetland ecosystems in the Philippines that is currently infested with janitor fish),they were found to contain heavy metals on their skin/in the flesh (data is available at the BFAR 13 Fish Health Office), particularly, mercury, a chemical that is detrimental to both humans and lower forms of life. This is the reason why we are not considering feed conversion in the management scheme. I think, the best way to eliminate the fish is to convert it to other useful goods other than feeds. Also, we are finding ways to eliminate them based on the perspectives of capture fisheries, habitat studies (burrowing holes/behavior) and feeding behavior.

M. Hubilla-Travis
Agusan Marsh Volunteer Researcher
Agusan del Sur

jc said...

M. Travis,

Please email me at There may be a lot of good things that we can talk about in regard to the Janitor fish. Thanks!

Anonymous said...

is it possible to derive an anti-microbial extract from the digestive tract of the janitor fish?

MOMEntum said...

it can also be used as a water purifier.

Anonymous said...

im a community organizer in laguna lake im interested in finding solution to this(janitor fish) predator. if you have a reseach and/or experimentation please share with us.

my email:

jc smith said...

Hi Jonathan, I will ask Ms. Travis, an authority on Janitor fish, if she can correspond with regarding this.


Anonymous said...

good day to everyone..
we are having our thesis ryt now, and im pursuing the topic about alternative energy source..
im from marikina city in the Philippines and that's one of the problems that marikina is trying to solve-the growing number of janitor fish in the marikina river..

can anyone help us out in here

my email: gilbert_quibal@YAHOO.COM

Anonymous said...

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Anonymous said...

Genial fill someone in on and this post helped me alot in my college assignement. Thank you as your information.

me + you = ♥ said...

Hi there! I'm a 4th yr High school student from Zambales and we are having a Project proposal in research. I'm very interested about the utilization of janitor fish. And i'm wondering if it's really possible that it can be used as a water purifier? can you share me some information regarding this?

here's my e-mail address:

thank you everyone :))

Gaelle said...

Hi, I'm a college student researching on the feasibility of turning janitor fish skin into leather or a similar kind of material. Would anyone have information regarding the process? Thanks!

My email address is


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