Janitor Fish: From the Amazon to Pasig River
The Janitor Fish story from the Pasig River shows that even good intentions can backfire without foresight. In leadership and policy, wisdom means pausing before acting—aligning compassion with context to prevent unintended harm.
Once upon a (very real) river — the Pasig River — a curious little fish began to appear. It had a bony armor, a mouth like a suction cup, and an appetite for algae. Locals began calling it the janitor fish, the “cleaner” that might finally help restore a river long choked with waste.
“Janitor fish (Pterygoplichthys); Image source: Esquire Philippines
In a country where every small act of hope counts, people thought — maybe this fish is heaven-sent.The janitor fish wasn’t a native at all. It hailed from the Amazon River Basin in South America — a natural scrubber in aquariums, not in open rivers.
According to Esquire Philippines (2023), these fish were imported in the 1980s–1990s by aquarium hobbyists. Because they were hardy, they became popular. But as they grew — sometimes up to two feet long — owners ran out of space.
Out of kindness or convenience, many released them into creeks and rivers, believing they’d simply live freely there (Phys.org, 2011).
When the Cleaners Turns Into Trouble
Janitor fish found paradise in its new home — the Pasig–Marikina–Laguna de Bay river system. Polluted waters didn’t bother it. Few local predators could eat it. It multiplied fast, burrowed deep, and fed on what native fish needed. Field accounts and local studies note displaced native fish, weakened riverbanks due to burrowing, and damaged nets (see LPU Laguna Study, 2022 and Esquire PH). By the 2000s, janitor fish reportedly made up ~75% of small fishers’ daily catch in some areas (GMA News, 2007).
Local agencies explored practical responses — including buy-back or “cash-for-catch” schemes to remove biomass and convert it to fishmeal or fertilizer. A mid-2000s report cites an LLDA rate of ₱10/kg (PhilStar). Such steps likely helped in spurts, yet the fish were already well established and biologically advantaged in degraded waters — making long-term reversal difficult without broader habitat recovery.
The Law of Unintended Consequences
Economists call this the Law of Unintended Consequences: actions often produce effects that are unanticipated or unintended. No one planned a river invasion. No one meant harm. But a series of small, seemingly harmless choices — importing, releasing, ignoring — created a cascade of damage. In leadership, it’s the same story: programmes and reforms launched because they “feel right” can falter when the context isn’t ready, people aren’t aligned, or the system can’t support them. Good intentions are not enough; foresight is what makes them sustainable.
Doing the Wrong Thing Efficiently
Management thinker Peter Drucker once said: “There is nothing so useless as doing efficiently that which should not be done at all.” — widely attributed to Peter F. Drucker in The Effective Executive (1967); see Goodreads quote reference. The janitor fish story reminds us: even the best execution can’t redeem a misaligned idea. Releasing the fish was efficient, compassionate, even logical — but not wise. Effectiveness without alignment is just motion without meaning.
The Precautionary Principle
In environmental ethics, there’s the Precautionary Principle: When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause-and-effect relationships are not fully established scientifically. (Wingspread Statement, 1998). Had this principle been followed, the janitor fish might still be in aquariums, not in rivers. And in leadership, it’s a principle worth practicing: when in doubt, pause; when unsure, assess; when tempted to act fast, think long. Foresight is humility in action — the discipline to question your own certainty.
The ASK Framework: From Good Intentions to Wise Actions
💡 The ASK Takeaway
The Janitor Fish story shows how good intentions can backfire without foresight—echoing the heart of our
ASK Framework — Align • Strengthen • Knit:
- Align your actions with purpose, ecosystem, and long-term impact before execution.
- Strengthen your systems with research, testing, and consultation to anticipate consequences.
- Knit people, data, and values together—wisdom grows when perspectives converge.
Foresight is humility in motion—pause, align, strengthen, and knit before acting.
Frequently Asked Questions
What does the janitor fish story teach about leadership?
It reminds leaders that good intentions without foresight can cause harm. Effective leadership requires assessing long-term consequences before acting.
How does the Law of Unintended Consequences apply to leadership?
When leaders act without full context or stakeholder alignment, well-meant initiatives can create new problems. Foresight and consultation prevent avoidable fallout.
What is the Precautionary Principle and how can leaders use it?
The principle means taking preventive action even when evidence is incomplete. Leaders practice it by pausing, assessing, and seeking counsel before major decisions.
How does the ASK Framework relate to this story?
Align intentions with purpose and ecosystem impact, Strengthen plans through due diligence and testing, and Knit people and insights together for wiser decisions.
What is the key takeaway for modern leaders?
Don’t just do things right—make sure you’re doing the right things. Foresight, humility, and alignment turn good intentions into sustainable impact.
