Scientists Find Tiny Orange Amazon Fish in Just Three Pools, Urge Protection

A team of Brazilian and U.S. researchers has described a new species of tiny, brightly marked fish from the Amazon, and they say it may already qualify as endangered. According to ScienceDaily, which relayed a release from Pensoft Publishers, the fish has been found in only three small forest pools in northern Brazil.

The species is named Laimosemion laranja. It is a killifish, a group of small freshwater fish, and measures less than three centimeters in standard length. The researchers have recommended expanding a nearby protected reserve to cover the places where it lives.

What the new fish looks like and where it was found

Males have rows of bright orange spots along the front half of the body, followed by bold orange chevron patterns near the tail. The markings contrast with pale gray sides. Lead researcher Yuri Abrantes of the Universidade Federal do Rio Grande do Norte said both males and females had coloration unlike anything the team had seen in the study area.

The fish turned up during fieldwork in the Rio Cajari drainage in southern Amapá, a state in northern Brazil. The team was sampling small rivers known locally as igarapés as part of a project on how life-history strategies evolved in freshwater fish of the family Rivulidae. Abrantes said the “very striking coloration” caught their attention right away.

The research team included scientists from the Universidade Federal do Rio Grande do Norte, Instituto Peixe das Nuvens, Universidade Federal do Pará and the University of West Florida.

How researchers confirmed it was new

Color alone was not enough to call it a new species. According to the report, the team examined the fish’s body proportions, counted its scales and studied features of its skeleton. They compared those traits with closely related species and analyzed its mitochondrial DNA. The genetic testing confirmed that the fish was a previously unrecognized species.

The name comes from the Portuguese word for orange, which covers both the color and the fruit. It also honors Laranjal do Jari, the municipality in Amapá where the species was found. Abrantes said the team wanted a name that would highlight a feature of the fish and build a connection with local people.

A window into how Amazonian killifish evolved

The find may also help scientists understand the evolution of the group. Some killifish have adapted to pools that periodically dry out. Their embryos stop developing and stay dormant in damp mud, then resume growing when seasonal rains refill the pools. Abrantes said Laimosemion is one of five independent origins of this annual life cycle within Rivulidae, and that the new species expands knowledge of the group’s diversity and evolution in the region.

Why it matters: a small range under pressure

The significance of the discovery goes beyond one colorful fish. The researchers say it shows how much remains unknown in parts of the Amazon that are poorly studied and increasingly threatened.

Every known location of the fish shows signs of disturbance, according to the report. One pool is close to water discolored by sediment from mining. Another lies inside the city, where plastic pollution is affecting the environment. Deforestation and urban development are also putting pressure on the surrounding habitat.

The species’ entire known range is estimated at 25 square kilometers. Because the habitat is so restricted and faces several threats, the researchers believe the fish meets the criteria for the Endangered category under guidelines from the International Union for Conservation of Nature. That is the team’s assessment based on those criteria, not a formal listing announced in the report.

For readers, the case is an example of how species can be identified only after their habitats are already under strain. A fish found in three pools has little room for error if those pools are polluted or lost.

What the researchers recommend

To improve the fish’s chances, the team proposes expanding the boundaries of the Rio Cajari Extractive Reserve to include the areas where it lives. Abrantes said the discovery was an opportunity to draw attention to conserving areas that are still poorly explored but highly threatened.

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Around Prague, based on reporting by ScienceDaily