A Colorful New Species Has Been Hiding In Our Aquariums For Nearly 20 Years

Every year, scientists classify between 15,000 and 18,000 new species. Newly discovered animals inevitably attract the most public attention, but researchers also log many new plants, fungi, and other forms of life. Not every species classified is strictly "new," in the way you might expect, because thousands of discoveries actually come from reclassifying lifeforms that were once thought to belong to a certain species, but which closer scientific scrutiny proves is actually unique. As the quest to classify Earth's life surges on, 2025 has brought just such a discovery: a colorful little crayfish that was kept in aquariums for over a decade without anyone realizing it was something special.

In the early 2000s, aquarium owners around the world fell in love with a type of crayfish being exported from Indonesia under the names "Blue Moon," "Hoa Creek," and "Irian Java" crayfish. They surged in popularity thanks to their mix of blue and purple colors. However, the crayfish exports weren't identified with a scientific name, so in 2023, a group of researchers in Czechia ordered a shipment of the crustaceans to see what they really were. They discovered that the popular pet was actually multiple crayfish species with similar appearances, and one of them had never before been identified in scientific literature. In a paper published in the journal Zootaxa earlier this year, the research team unveiled its finding, along with a proper scientific label, Cherax pulverulentus.

The discovery of C. pulverulentus is a primer in how scientists identify previously unclassified or improperly classified species. After members of the Czech research team noticed subtle differences in the proportions and colors of certain crayfish, they took DNA samples from six individuals. The analysis revealed that at least 2% of these crayfish's genome is unique from the most closely-related species on record. Their new scientific name is Latin for "dusty crayfish," chosen because of the animal's lightly speckled shells.

With C. pulverulentus being brand new to the scientific world, researchers only know the basics about this species for now. It is endemic to eastern New Guinea, and like all crayfish, it lives in freshwater systems, and can get oxygen even when burrowed under the mud. It also shares its fellow crayfish species' aggressive attitude, making it not the most eager critter to be studied. The species is slightly larger than the average crayfish, topping four inches in length.

There are two distinct varieties of C. pulverulentus, distinguished by their colors. The blue subtype has a dark hue with orange on its legs and tails, while the purple subtype is brighter, with a turquoise shell coated in purple dots and white patches where the blue variety is orange.

Properly identifying species is one of the most important pursuits in the fields of science. Each time researchers distinguish a species, it opens the door to a better understanding of how ecosystems function, and how we can help to foster a healthier planet in the face of environmental changes, habitat loss, invasive species, and other threats to wildlife. A crustacean the size of a playing card whose primary role in human lives is as an aquarium novelty may not seem like the most groundbreaking species to classify, but the results of this study are already leading to new discoveries.

The island of New Guinea, to which the species is endemic, is currently facing several serious climate threats, including deforestation and the extraction of oil, gas, and precious minerals, which are especially damaging to the watersheds that C. pulverulentus calls home. Researchers are now turning their attention to observing the species in its natural habitat and understanding its role in that fragile ecosystem.

Another issue highlighted by the discovery of C. pulverulentus is the growing threat of invasive species. Introducing non-native species is a key factor affecting the biodiversity of ecosystems, and the fact that this particular crayfish was shipped all over the world without anyone knowing what it really was raises major concerns. Researchers have already discovered a blue C. pulverulentus in a spring in Hungary, 8,000 miles from its native habitat. Who knows where else it could be loose?