Animal & Veterinary

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 to find 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. In the aquaculture industry, the term “fish” refers collectively to finfish, mollusks, crustaceans, and other farm-raised aquatic animals.

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. Currently, about half of the fish eaten by people globally are 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, channel catfish, 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 drug is safe, effective, properly manufactured, and properly labeled, 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 drugs the only drugs that can be legally used in fish?

Besides approved drugs, there are two other categories of legally marketed animal drugs—conditionally approved animal drugs and indexed animal drugs—that may be used in fish, depending on the situation. Only drugs for minor species or for a minor use in a major species can be conditionally approved and only drugs for certain minor species can be indexed.

FDA classifies horses, dogs, cats, cattle, pigs, chickens, and turkeys as the seven major species. All other animals, including fish, are minor species.

Conditional Approval

A conditionally approved animal drug has gone through the New Animal Drug Application 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 then submits an application to FDA for full approval. FDA 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.” Although technically unapproved, a drug listed on the Index has legal marketing status. It can be legally marketed for a specific use in certain 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 food-producing animals; 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 a three-step process. A panel of qualified experts outside FDA reviews the drug’s safety in the specific minor species. The panel also reviews the drug’s effectiveness for the intended use. All members must agree that, when used according to the label, the drug’s benefits outweigh the risks to the treated animal. The panel submits a report containing its recommendation to FDA. 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 manner other than what is stated 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?

It’s not always easy to tell if an aquaculture drug is legally marketed, meaning if it’s approved, conditionally approved, or indexed. 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 list the six-digit NADA or ANADA number and the statement, “Approved by FDA,” on the drug’s label, although they aren’t required to do so.

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:

“NOT APPROVED BY FDA. Legally marketed as an FDA Indexed Product under MIF XXX-XXX. Note—In order to be legally marketed, an animal drug product intended for a minor species must be Approved, Conditionally Approved, or Indexed by the FDA. THIS PRODUCT IS INDEXED.

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 the online publication, Approved Animal Drug Products, called the “Green Book” for short. FDA publishes the Green Book in its entirety every January and updates it monthly. 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 FDA-approved for animals?

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Does FDA assess the effect of aquaculture drugs on the environment?

The National Environmental Policy Act requires FDA to assess how the environment will be affected if an animal drug is approved or indexed. 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.

Before the aquaculture drug can be approved or indexed, FDA reviews the company’s environmental assessment and must determine that the drug won’t cause significant environmental effects. If FDA determines that the aquaculture drug will significantly affect 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?

If your pet fish becomes sick, 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 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 products contain the amount of active ingredient claimed on the label or whether they are safe, effective, and properly manufactured. (See the section above entitled, “How can I tell if an animal drug is approved, conditionally approved, or indexed?”)

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 pagedisclaimer icon or’s online database of aquatic animal veterinariansdisclaimer icon.

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What should I do if my pet fish has a bad reaction to a drug or doesn’t respond to treatment?

If your pet fish has a bad reaction to a drug or doesn’t respond to treatment, FDA encourages you to report the problem. Problems with any animal drug—approved, conditionally approved, indexed, or unapproved—include adverse drug events and product defects. Adverse drug events are undesired side effects associated with a drug or a lack of effect (the drug doesn’t do what it’s expected to do). Adverse drug events also include unfavorable reactions in people who handle the drug. Product defects are problems such as defective packaging or an abnormal appearance of the drug.

For a legally marketed animal drug—one that is approved, conditionally approved, or indexed—FDA encourages you to report adverse drug events and product defects 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 drug events and product defects 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 drug events and product defects to FDA.

How to Report Animal Drug 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 not be labeled or advertised appropriately or truthfully.

With no FDA review of an animal drug, there’s no way for veterinarians, fish biologists, fish owners, and others to know if a drug is safe and effective or if its manufacturing process is adequate to maintain the drug’s quality and consistency from batch to batch. Also, because there are no reporting requirements of adverse drug events and product defects for unapproved animal drugs, problems with these drugs may be slow to be identified.

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Page Last Updated: 04/29/2016
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