Fish and Aquatic Conservation

Aquaculture Medications

Paddlefish can be distinguished from other freshwater fish by the presence of a very large mouth, and a long, paddle-shaped snout (called a rostrum) that is about one third the length of the body. Credit: Doug Canfield/USFWS

Drug Use Guidance

Looking for information to help you make an informed decision on what fish drug to use to meet your fisheries management objective(s)? Look no further. Below is information on (1) FDA approved fish drugs, (2) fish drugs available through the AADAP National INAD Program, (3) and fish drugs of low regulatory priority.

FDA approved fish drugs

  1. Chorionic Gonadotropin (Chorulon®)
  2. Formalin (Parasite-S, Formalin-FTM, Formacide-B)
  3. Hydrogen Peroxide (35% Perox Aid®)
  4. Chloramine-T (Halamid® Aqua)
  5. Oxytetracycline Hydrochloride (several products available)
  6. Tricaine Methanesulfonate (Tricaine-S)
  7. Florfenicol (Aquaflor®)
  8. Oxytetracycline dihydrate (Terramycin® 200 for Fish)
  9. Sulfadimethoxine & Ormetoprim (Romet® 30 & Romet® TC)

Note that (1) approved drugs can only be used for specific purposes, unless extra-label use is prescribed (where appropriate) by a veterinarian, and (2) FDA approves a product, not the active ingredient. For more detailed information, refer to the following

Low Regulatory Priority (LRP) Drugs
LRP drugs are innocuous compounds that have historically been used in aquaculture but will likely never be approved by FDA. The FDA Center for Veterinary Medicine (CVM) has determined these compounds to be of low regulatory priority (LRP). CVM is unlikely to take regulatory action for use of LRP substances as long as they are used according to these rules (scroll down to page 14). For more information on how CVM described LRP products listed below, click here and scroll down to What about products I hear referred to as “low regulatory priority”?

    Acetic acid - parasiticide
    Calcium chloride - egg hardening
    Calcium oxide - protozoacide
    Carbon dioxide gas - anesthetic
    Fuller’s earth - reduce egg adhesion
    Garlic – parasiticide
    Ice - reduce metabolic rate
    Magnesium sulfate - parasiticide
    Onions - parasiticide
    Papain - remove egg mass gelatinous material
    Potassium chloride - osmoregulation
    Povidone iodine - egg surface disinfectant
    Sodium bicarbonate - anesthetic
    Sodium chloride - osmoregulation; parasiticide
    Sodium sulfite – improve egg hatchability
    Thiamine hydrochloride - thiamine deficiency in salmonids
    Urea and tannic acid - denature egg adhesion
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Guide to Using Drugs

A close view of salmon eggs and developing salmon fry. Credit: USFWS

The Guide to Using Drugs, Biologics, and Other Chemicals in Aquaculture (Guide) is a comprehensive introduction to the legal and judicious use of regulated products in aquaculture and is a great resource for fish culturists and fish health biologists involved in fish culture. The Guide describes regulated fish products (i.e., drugs, biologics, disinfectants, and pesticides) that are approved for use in the U.S as well as Investigational New Animal Drug (INAD) exemption and low regulatory priority (LRP) drugs that can be used in U.S. aquaculture and fisheries management.

The Guide is intended for informational and educational purposes only. We recommend that those using the Guide should read the PREFACE and be aware that it’s the responsibility of individuals administering regulated products to read and follow label instructions and be aware of any changes to relevant regulation prior to using these products.

There is also an easy to use Treatment Calculator available in both Excel 97-2003 (.xls) and Excel 2010 (.xlsx) that you can use to assist you in calculating how much drug needs to be added to a static or flow through tank to achieve the drug target dose.


A sponsor can apply for Designation status for Minor Use and Minor Species (MUMS) drugs prior to their approval or conditional approval and be eligible for incentives to support the approval or conditional approval of the designated use.

When a drug is designated for a particular intended use, the sponsor of the drug obtains seven (7) years of exclusive marketing rights upon approval (or conditional approval) of the drug for that intended use. Each designation that is granted must be unique, i.e., only one designation can be granted for a particular drug substance in a particular dosage form for a particular intended use. The intended use includes both the target species and the disease or condition to be treated.

A sponsor of a designated new animal drug is also eligible to apply for grants to defray the cost of studies to support approval or conditional approval of the designated intended use. The availability of these grants is announced periodically and a notice is posted to this website at that time.

Public data generating partners, like AADAP, can also apply for MUMS grants as long as the drug is designated for the particular claim that the research will support and that the sponsor provides a letter to the partner indicating that they support their research activities.

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Veterinary biologics are products designed to diagnose, prevent, or treat diseases in animals. Although the term “biologic” can potentially refer to a wide range of products, those used in fish are generally classified as vaccines or bacterins: vaccines contain live organisms (bacteria or viruses) or killed viruses, whereas bacterins contain inactivated cultures of bacteria. Both are used to increase the natural ability of the animal to resist the disease caused by the organism from which the biologic product is derived. Biologics differ from drugs functionally (biologics affect the fish’s immune system while drugs affect the disease-causing agent) and in terms of how they are applied (preventative, before infection application vs. therapeutic, post-infection application). Also, most biologics leave no chemical residues in animals.

For more information on biologics and a list of licensed, commercial veterinary biologics that are currently approved for use in fish, visit the AFS Fish Culture Section Guide to Using Drugs, Biologics, and Other Chemicals in Aquaculture.

Clove Oil

Clove oil is still commonly used as a fish sedative in the United States, in spite of the fact that it is not approved by the U. S. Food and Drug Administration (FDA) for such use. In 2002, the FDA’s Center for Veterinary Medicine issued Guidance on Use of Clove Oil and Eugenol on FIsh. The Guidance states that neither clove oil nor any individual active ingredient of clove oil (eugenol, isoeugenol, or methyleugenol) is approved for use for the anesthesia of fish. Therefore, the use of either clove oil or eugenol as an anesthetic for fish makes them unapproved new animal drugs.

Bottom line – it is illegal to use clove oil as a sedative/anesthetic on fish in the United States.

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Immediate Release Sedative

Access to safe and effective fish sedatives is a critical need of fisheries researchers, managers, and culturists. Federal, state, private, tribal, and academic fisheries professionals routinely sedate fish for transport (e.g., moving fish to a captive holding facility, transporting to stocking sites or to market), collection of tissue samples (e.g., scales, spines, gametes, fin clips) or morphometric data (e.g., length, weight), and surgical implantation of tags or tracking devices (e.g., for monitoring movement, spawning behavior, or survival). Ideally, a fish sedative is easy to administer, safe to use, effective at low doses, provides quick and predictable sedation, offers some analgesia, elicits a state of sedation that is easily managed, has a reasonable margin of safety with respect to over-sedation, can be used over a broad range of water chemistries, allows for rapid recovery from sedation and physiological responses to the sedative, and is inexpensive. Additionally, it is often desirable that the sedative have no withdrawal period, meaning sedated fish can be immediately released into the wild or taken to market upon recovery (typically referred to as“immediate-release”). Unfortunately, there are few fish sedatives that possess all of these qualities, and, at this time, there are none that can be legally used in North America without a lengthy withdrawal period.

Since 2009, efforts have been underway to generate data needed to support a U. S. Food and Drug Administration approval of AQUI-S20E (10% eugenol; AQUI-S New Zealand Ltd., Lower Hutt, NZ), a candidate immediate-release sedative for use in the United States. AQUI-S20E is currently available under the FWS Investigational New Animal Drug exemption authorization as an immediate-release sedative where freshwater and marine fish can be sedated to handleable under field applications and returned immediately back into public waters. All other uses (i.e., hatchery use, transportation) require a 72-h withdrawal period.