Dr Hiranya Sudasinghe: Can Saving One Aquarium Fish Harm Thousands of Wild Animals?

STORY 5 OF 10: Part of a series of short stories inspired by our conversation with Dr Hiranya Sudasinghe, sharing what years of experience have taught them to see.

Tinfoil Barb in a home aquarium

The fish was attractive when it was small.

Now it is enormous, permanently hungry and occupying a tank designed for something less ambitious.

The owner faces an unpleasant choice.

Killing it feels cruel.

Releasing it into a river feels kind.

The problem is that rivers already contain animals.

A non-native aquarium fish may prey upon local species, compete for food, introduce disease or reproduce and spread through connected waterways.

The individual fish has been saved.

The ecosystem has been handed a stranger with no return ticket.

An exotic species is one that has been moved beyond its natural range through human activity.

Not every exotic species becomes invasive.

But one that establishes, reproduces and spreads may cause serious harm, particularly in a freshwater system where native animals have not previously encountered a similar predator or competitor.

A single release may not remain a single animal.

It may become a breeding population.

Tinfoil Barb retrieved from a local stream, a clear visual record of an introduced aquarium species found in wild waters. Photograph courtesy of Hiranya Sudasinghe.

Hiranya’s words that inspired this story

“We like to save lives of animals irrespective of whether they are exotic species or not, so we just release them; we think it’s a good spirit.”

“Your intention may be good in terms of the individual animal but it’s not a good thing for the whole ecosystem.”

Why it matters

A released animal may

• Become a predator

• Compete with native fishes

• Introduce parasites or disease

• Reproduce

• Spread through connected waterways

• Become extremely difficult to remove

  
  

What this changes

Never release aquarium fishes, turtles, plants or other pets into rivers, streams, canals, reservoirs, village tanks or wetlands.

Seek responsible rehoming through experienced keepers, reputable dealers, aquarium specialists or appropriate organisations.

Compassion should not end with the animal in your hands.

It should include the animals already living in the water.

Next beneath the surface

Some species already have the protection of the law.

But what changes in the stream after their names are placed on a protected list?

Next: Can a Species Be Protected by Law and Still Be Left Unprotected?

Previous: Could Tidying a Stream Be the Worst Thing You Do to It?

Meet Dr Hiranya: Read He Chose the Fish