Goodea fish are popular with aquarium hobbyists Jiri PListil / Alamy Stock Photo

Keeping fish as a hobby can harm wildlife – but it can also help save endangered species. Dedicated aquarium enthusiasts are keeping alive 30 fish species now believed to be extinct in the wild and helping preserve hundreds more species.

“Many species already extinct in the wild only exist because they are being kept and bred by these hobbyists,” says Jose Valdez at Aarhus University in Denmark.

The pet trade is often part of the problem. For instance, clownfish vanished from some reefs after they became wildly popular as pets after the 2003 movie Finding Nemo was released. Marine fish are still sometimes caught alive using cyanide, which damages coral reefs. And many harmful invasive species are releases or escapees from aquariums.


“There are cases in which the pet trade has been harmful,” says Kapil Mandrekar at the State University of New York. But many fish are now bred in captivity or caught on a sustainable basis with the help of local communities, he says.

The CARES (Conservation, Awareness, Recognition, Encouragement, and Support) Fish Preservation Program, founded by enthusiast Claudia Dickinson in 2004, is doing much more. It is encouraging fish-keepers to keep, breed and exchange endangered fish to help preserve viable populations.

CARES has compiled its own priority list of nearly 600 freshwater fish, which has now been assessed and compared with official lists of endangered species by Valdez and Mandrekar. The pair found 80 of the species on the CARES list have yet to be formally described by scientists.

The list of species CARES says is extinct in the wild also includes 30 additional species to those on the Red List of threatened species maintained by the International Union for Conservation of Nature. Members of the preservation programme are keeping populations of these alive.

Many of the species on the CARES list have no commercial value as pet fish, and aren’t charismatic enough for many conservation organisations, says Mandrekar. So if they weren’t on the list no one would be doing anything to preserve them.

The pair didn’t independently check the assessments by CARES. But Valdez says many of the hobbyists dedicate their time to certain fish and even go on field trips to study them in the wild.

“Since they are passionate and are directly involved with these fish they are more knowledgeable than scientists, who don’t have the luxury to study a small subset of fish in a particular lake or travel to remote areas for a scientifically non-important fish species,” says Valdez.

If you want to help save species you can take part, too, says Mandrekar. “As long as you have a good understanding of how to care for an aquarium it’s something you can get involved in.”

Journal reference: Fishes, DOI: 10.3390/ﬁshes4040049