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Aquaculture and Aquaculture Drugs Basics

Have you ever wondered where the koi in your local park’s pond come from, or the bettas at the pet store, or the tilapia at the grocery store? Have you ever thought about what happens if fish get sick? Are there drugs available to treat them? Read below for the answers to these questions and to find out more about the field of aquaculture.

What is aquaculture?

Think of aquaculture as aquatic animal farming. People breed, raise, and care for aquatic animals in controlled environments, such as tanks, ponds, and offshore cages. Both saltwater and freshwater fish are grown in the U.S. for people’s food; for repopulating ponds, rivers, and streams; and for the aquarium trade.

Many kinds of food fish—fish that will enter the human food supply—are routinely farm-raised and represent an important source of animal protein for people around the world. Food fish include finfish, such as catfish, salmon, trout, and tilapia; and shellfish, like oysters, clams, shrimp, and crabs. More than half of all fish eaten by people globally is farm-raised.

Not all aquaculture involves the commercial sale of food fish. Federal and state agencies raise a wide range of fish species (trout, salmon, bluegill, largemouth bass, walleye, and redfish, to name a few) to boost fish populations in the wild. Ornamental fish, including tetras, barbs, danios, bettas, and koi, are often displayed in home or public aquariums and in garden ponds. The ornamental fish trade is a multi-million dollar business in the U.S.

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How does FDA help keep fish healthy?

Fish, like other animals, can get sick. Bacteria, fungi, parasites, viruses, and poor water quality can cause various diseases in fish. Fish producers and fish hatchery managers worry about fish health because diseases can kill many fish quickly.

FDA works to ensure that safe and effective drugs are available to treat fish diseases. The agency also works to ensure that treated food fish are safe for people and other animals to eat. Along with other government agencies, aquaculture groups, and fish health professionals, FDA promotes the proper use of legal aquaculture drugs. Through educational outreach, the agency also encourages research to support the approval of safe and effective aquaculture drugs.

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How is an aquaculture drug approved?

The basic approval process for an aquaculture drug is the same as the approval process for any animal drug. A drug company collects information about the safety and effectiveness of a new animal drug. Public agencies, such as the U.S. Fish and Wildlife Service, U.S. Geological Survey, U.S. Department of Agriculture, and state fish and wildlife agencies, may help collect the required safety and effectiveness data to support the approval of an aquaculture drug. Commercial fish farms and public fish hatcheries may also be involved in this research.

Based on the collected information, the drug company decides if there’s enough proof that the drug is safe and effective for the intended use. If so, the company submits a New Animal Drug Application to FDA for review. The application includes all the information about the drug and the company’s proposed label. If the application proves that the drug is safe, effective, properly manufactured, and adequately labeled and packaged, the agency approves the drug.

When FDA approves a drug, the agency is approving the final drug product, not the active ingredient alone. The final drug product includes both active and inactive ingredients.

An active ingredient is the pharmacologically-active component responsible for achieving the drug’s intended effect—for example, to treat a fish disease or to change the structure or function of a fish’s body. A drug may have one or more active ingredients. Inactive ingredients are all other components of the final drug product, such as coloring and flavoring substances, preservatives, and binding agents.

For example, the approved aquaculture drug 35% PEROX-AID contains the active ingredient hydrogen peroxide at a specific concentration. As part of the approval process for 35% PEROX-AID, the company showed that the final drug product was consistently manufactured to ensure strength, quality, and purity. The company also showed that the final drug product was safe and effective to control mortality due to certain fungal and bacterial fish diseases. Another product containing hydrogen peroxide as the active ingredient, even at the same concentration, isn’t the same as 35% PEROX-AID. Unapproved hydrogen peroxide products may not be safe or effective to treat fish diseases, and the quality and consistency of the manufacturing process cannot be assured.

Approved Aquaculture Drugs

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Are approved aquaculture drugs the only drugs that can be legally used in fish?

Besides approved aquaculture drugs, there are two other categories of legally marketed animal drugs that can be used in fish, depending on the situation. These two categories are: (1) conditionally approved animal drugs; and (2) indexed animal drugs.

Conditional Approval

A conditionally approved animal drug has gone through FDA's drug approval process except the drug has not yet met the effectiveness standard for full approval. FDA’s conditional approval means that when used according to the label, the drug is safe and has a “reasonable expectation of effectiveness.”

The conditional approval is valid for one year. The drug company can ask FDA to renew the conditional approval annually for up to four more years, for a total of five years of conditional approval. During the 5-year period, the drug company can legally sell the animal drug while collecting the remaining effectiveness data. This early marketing is good for two reasons: first, the drug is available sooner to be used in animals that may benefit from it; and second, the company can recoup some of the investment costs while completing the full approval.

After collecting the remaining effectiveness data, the company applies to FDA for full approval. The agency reviews the application and, if appropriate, fully approves the drug.

Conditional Approval Explained: A Resource for Veterinarians


An indexed animal drug is a drug on FDA’s Index of Legally Marketed Unapproved New Animal Drugs for Minor Species, referred to simply as “the Index.” As the name says, a drug listed on the Index is unapproved but has legal marketing status. It can be legally sold for a specific use in certain minor species. FDA classifies horses, dogs, cats, cattle, pigs, chickens, and turkeys as the seven major species. All other animals, including fish, are minor species.

Indexing is allowed for drugs for:

  • Non-food-producing minor species, such as ornamental fish. These fish are typically not eaten by people or by other animals that produce food for people to eat; and
  • An early non-food life stage of a food-producing minor species, such as oyster spat (immature oysters). Because people don’t generally eat oyster spat, a drug to treat a disease in spat can be indexed, but a drug to treat a disease in adult oysters, which people commonly eat, can’t be indexed.

Indexing a drug is quite different from the drug approval process. Indexing relies heavily on a panel of qualified experts outside FDA. The experts review the drug’s safety in the specific minor species and the drug's effectiveness for the intended use. All experts on the panel must agree that, when used according to the label, the drug’s benefits outweigh the risks to the treated animal. If FDA agrees with the panel, the agency adds the drug to the Index.

Drug Indexing

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How are approved, conditionally approved, and indexed aquaculture drugs used?

All approved, conditionally approved, and indexed aquaculture drugs should be used according to the label, which states:

  • The species of fish the drug is intended for;
  • The diseases or conditions the drug is to be used for; and
  • Specific directions for use.

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Can drugs that are approved for other animals or people be used in fish?

Because there are only a few approved, conditionally approved, and indexed aquaculture drugs, veterinarians sometimes need to use drugs approved for other animals or people in fish. In 1994, Congress passed the Animal Medicinal Drug Use Clarification Act. This law added provisions to the Federal Food, Drug, and Cosmetic Act (FD&C Act) that allow veterinarians to prescribe approved human and animal drugs for extra-label uses in animals under specified conditions. When an approved human or animal drug is used in a way that isn't listed on the drug’s label, it’s an extra-label use. This is commonly called “off-label” use because the drug is used in a way that is “off the label.”

Veterinarians must follow FDA’s extra-label drug use requirements, as stated in the FD&C Act and FDA regulations. It’s illegal to use a conditionally approved drug or an indexed drug in an extra-label manner. These drugs must be used exactly as stated on the label.

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How can I tell if an aquaculture drug is legally marketed?

Here are some tips to help you identify legally marketed aquaculture drugs.

Look at the drug’s label.

All FDA-approved animal drugs have a New Animal Drug Application (NADA) number, or for generic animal drugs, an Abbreviated New Animal Drug Application (ANADA) number. Many drug companies currently list the six-digit NADA or ANADA number and the statement, “Approved by FDA,” on the drug’s label. By the end of September 2023, all drug manufacturers will be required to list this information on the label of every approved animal drug.

Conditionally approved animal drugs also have a six-digit application number which appears on the drug’s label as part of the following required statement:

“Conditionally approved by FDA pending a full demonstration of effectiveness under application number XXX-XXX.”

Indexed animal drugs have a Minor species Index File (MIF) number. The six-digit MIF number appears on the drug’s label as part of the following required statements:

“LEGAL STATUS—In order to be legally marketed, a new animal drug intended for a minor species must be Approved, Conditionally Approved, or Indexed by the FDA. THIS PRODUCT IS INDEXED—MIF# XXX-XXX. Extra-label use is prohibited."

Check FDA’s website.

  • Look up the drug in Animal Drugs @ FDA. Most FDA-approved and conditionally approved animal drugs are listed in this searchable online database. The database allows you to search using several parameters, including proprietary name (also known as trade name or brand name), active ingredient, and application (NADA or ANADA) number. Indexed animal drugs are not listed in Animal Drugs @ FDA.
  • Look up the drug in the Green Book. Most FDA-approved animal drugs are included in a publicly available list called Approved Animal Drug Products, or simply the “Green Book” for short. FDA updates the Green Book in its entirety every month and you can find these monthly updates on Animal Drugs @ FDA. While the information in the Green Book is mainly used by companies wanting to manufacture and distribute generic animal drugs, it’s also a resource for the public. Conditionally approved and indexed animal drugs are not listed in the Green Book.
  • Look up the drug in FDA’s Index of Legally Marketed Unapproved New Animal Drugs for Minor Species.
  • Look up the drug in the list of Approved Aquaculture Drugs.

When checking FDA’s website, keep in mind that it’s the final drug product that’s approved, conditionally approved, or indexed, not the active ingredient. Let’s say you want to search for legally marketed aquaculture drugs containing the fictional active ingredient “chemical A.”

If an aquaculture drug containing “chemical A” as the active ingredient is: It will be listed in:
  • Animal Drugs @ FDA
  • The Green Book
Conditionally approved
  • Animal Drugs @ FDA
  • The Index

Other drugs for fish may contain “chemical A” as the active ingredient; however, if they aren’t approved, conditionally approved, or indexed, they are unapproved animal drugs and not legally marketed.

How can I tell if a drug is legally marketed for animals?

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How does FDA evaluate the impact of aquaculture drugs on the environment?

Under the National Environmental Policy Act, FDA must consider how the environment will be affected if the agency approves, conditionally approves, or indexes an animal drug. This requirement applies to all animal drugs, including aquaculture drugs.

In most cases for an aquaculture drug, the drug company prepares an environmental assessment to describe:

  • How much drug is expected to get into the environment;
  • The drug’s potential toxicity to aquatic life, and
  • Potential effects the drug’s use will have on the environment.

If FDA determines that the aquaculture drug will not significantly impact the environment based on the information in the drug company’s environmental assessment, the agency writes what’s called a “Finding of No Significant Impact.” If FDA determines that the aquaculture drug will significantly impact the environment, the agency writes an Environmental Impact Statement.

Environmental Impact Considerations

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Is it safe for me to eat fish treated with an aquaculture drug?

FDA is responsible for protecting consumers’ health and making sure the human food supply is safe. As part of the approval process for an aquaculture drug intended for food fish, the drug company must prove to FDA that food made from treated fish is safe for people to eat.

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What should I do if my pet fish becomes sick?

Fish show a variety of signs when they’re sick. If something isn't right with your pet fish, you should first check the water quality. Often, poor water quality is the cause of the problem. A general fish care manual can help you learn how to maintain proper water quality for your fish.

Most drugs for fish diseases that you find in pet stores have not been evaluated by FDA for safety or effectiveness. These drugs are unapproved and not legally marketed. Therefore, you don’t know whether these drugs contain the amount of active ingredient claimed on the label or whether they are safe, effective, properly manufactured, and adequately labeled and packaged. (See the section above entitled, “How can I tell if an aquaculture drug is legally marketed?”)

Some veterinarians see pet fish as patients and can diagnose your fish’s problem and recommend a treatment plan. The use of certain drugs in fish requires a veterinarian’s involvement. To find a fish veterinarian near you, go to the American Association of Fish Veterinarians’ Find a Fish Vet page.

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What should I do if I think my pet fish is having a side effect to a drug or isn't responding to treatment?

If you think your pet fish is having a side effect to a drug or isn't responding to treatment, FDA encourages you to contact a veterinarian who sees pet fish as patients (see the  American Association of Fish Veterinarians’ Find a Fish Vet page).

FDA also encourages you to report the problem. Problems with any aquaculture drug—whether it's approved, conditionally approved, indexed, or unapproved—are called adverse events and include:

  • Side effects in the treated fish, such as abnormal swimming or skin damage;
  • A lack of effectiveness (the drug doesn’t do what it’s supposed to do);
  • Side effects in people who handle the drug, such as rashes, headaches, or nausea;
  • Medication errors, such as giving the wrong drug or the wrong dose; and
  • Product defects, such as a broken seal or the drug is off-color.

For a legally marketed aquaculture drug—one that is approved, conditionally approved, or indexed—FDA encourages you to report any adverse event in either fish or people to the drug company. Federal law requires drug companies to submit to FDA all reports of problems with legally marketed animal drugs that they receive. The required reporting of adverse events allows FDA to more easily identify and correct problems with approved, conditionally approved, and indexed animal drugs.

For unapproved animal drugs, you can voluntarily report adverse events to FDA.

How to Report Animal Drug and Device Side Effects and Product Problems

ADE Reporting for Fish Drugs: Information for Fisheries on How to Report Adverse Drug Events

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What are FDA’s concerns about unapproved animal drugs? Why should I care?

Unapproved animal drugs are animal drugs illegally marketed in the U.S. that haven’t been approved, conditionally approved, or indexed by FDA. The agency has serious concerns about unapproved animal drugs because they potentially put the health of animals and people at risk. These drugs are not reviewed by FDA and may not meet the agency’s strict standards for safety, effectiveness, and quality. Unapproved animal drugs also may be inadequately labeled and packaged.

Because unapproved animal drugs don’t go through FDA’s review process, veterinarians, fish biologists, and fish owners have no way to know if these drugs are safe and effective or if their manufacturing processes are adequate to maintain quality and consistency from batch to batch. Also, because drug companies aren't required to report adverse events for unapproved animal drugs to FDA, it may take more time for problems with these drugs to be identified.

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Resources for Aquaculture Professionals

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