A new rule that became effective in October clears the way for sponsors of drugs intended to treat fish and other minor species to legally market the drugs.

The regulation describes the criteria that the Food and Drug Administration’s Center for Veterinary Medicine will use for granting or denying requests to designate a new animal drug as a minor use or minor species drug. Major animal species are cattle, swine, chickens, turkeys, horses, dogs and cats; all others are considered minor species.

The MUMS Act establishes new regulatory procedures that provide incentives intended to make more drugs legally available to veterinarians and animal owners for the treatment of minor animal species and minor (uncommon) diseases in major animal species.

To encourage the development of these limited-demand drugs, the rule will grant drug sponsors seven years of exclusive marketing rights.