If you tried to invent the perfect caretaker for the Caribbean’s fragile coral reefs, it would be hard to top what nature already has created—the parrotfish.

And thanks to a court victory this week, these strikingly colored butlers of the sea will get help in carrying out their mission of removing remove algae that can smother and kill coral reefs.

Parrotfish nibble on small bits of coral, removing algae and stimulating new growth. Dead remnants of coral are then neatly excreted as sand. One parrotfish can create up to 200 pounds of sand each year, replenishing the idyllic beaches as the reefs experience a continual rebirth.

But fishing pressure is preventing this dutiful custodian from fulfilling its role in promoting the growth of the Caribbean’s endangered staghorn and elkhorn corals—the Caribbean’s key reef builders. With declines of 98 percent since the 1970s, both coral species are now protected under the Endangered Species Act.

Parrotfish, meanwhile, are being caught faster than they can replenish themselves, resulting in both smaller and fewer numbers of fish. Scientific studies show that small parrotfish are not as effective at clearing reef habitat as large ones.

To address this issue, in January 2012 Earthjustice sued the National Marine Fisheries Service on behalf of conservation organizations CORALations and Center for Biological Diversity and Mary Adele, arguing the agency is putting the reefs in grave danger by not considering the species’ critical custodial role when setting catch limits.

This week, federal district court judge Salvador E. Casellas agreed that the fisheries service was not properly protecting staghorn and elkhorn corals. The agency must now do a better job monitoring the effects of commercial fishing on coral in the U.S. Virgin Islands and Puerto Rico. One step will be to know how many fish there are—baseline studies were not done before the fishery was approved.

Every resident of the Caribbean, as well as every tourist seeking to dive among the reefs, has a stake in the health of coral reefs. These complex and intricate labyrinths of limestone are economic powerhouses.

The World Resources Institute, in partnership with government and non-government agencies, estimates that the dive industry contributes $2.1 billion annually to the economies of the Caribbean. In addition, the sale of fish and shellfish that make their homes in and around coral reefs accounts for more than $300 million each year.

The court’s decision will help protect the crucial relationship between parrotfish and coral keeping this essential ecosystem functioning for the benefit of both humans and marine life.