DK Hardware Supply

This letter concerns your firm's distribution of animal drug products for use in aquarium fish.

In March 2026, the United States Food and Drug Administration (FDA) reviewed your website (https://www.dkhardware.com) where you take orders for the following products sold under various brands: Amoxicillin, Cephalexin, Ciprofloxacin, Doxycycline, Metronidazole, Penicillin, Sulfamethoxazole/Trimethoprim.

The claims on your website establish that these products are intended for use in the cure, mitigation, treatment, or prevention of diseases in animals, which makes them drugs under section 201(g)(1)(B) of the Federal Food, Drug, and Cosmetic Act (the FD&C Act) [21 U.S.C. § 321(g)(1)(B)]. In addition, these animal drugs are misbranded under section 502(o) of the FD&C Act [21 U.S.C. § 352(o)] because they have not been drug listed with FDA, nor have they been manufactured in a facility that is registered with FDA in accordance with sections 510(b) and (j) of the FD&C Act [21 U.S.C. § 360(b), (j)]. As discussed below, introducing or delivering these unapproved and misbranded new animal drugs for introduction into interstate commerce violates section 301(a) of the FD&C Act [21 U.S.C. § 331(a)].

Examples of claims observed on your website (https://www.dkhardware.com) that establish the intended use of these products as drugs include, but may not be limited to, the following:

Fin Mox (Amoxicillin), 250 mg and 500 mg capsules, according to images of the product labels on your website:o “Antibiotics”o "FOR CONTROL OF COMMON BACTERIAL INFECTIONS IN FISH”

Aqua Soma Labs Fix Mox 250 (Amoxicillin), 250 mg capsules, according to an image of the product label on your website:o “Antibacterial fish medication”o “For Treatment of Common Bacterial Infections”

Aqua Soma Labs Fix Flex 250 (Cephalexin), 250 mg and 500 mg capsules, according to images of the product labels on your website:o “Antibacterial Fish Medication”o “For Treatment of Common Bacterial Infections”

Fin Flex (Cephalexin), 250 mg and 500 mg capsules, according to images of the product labels on your website:o “Antibiotics”o “For Control of Common Bacterial Infections in Fish”

Fish Ceph (Cephalexin), 500 mg capsules, according to an image of the product label on your website:o “Antibacterial Fish Medication”

Fin Flox (Ciprofloxacin), 500 mg tablets, according to an image of the product label on your website:o “FOR CONTROL OF COMMON BACTERIAL INFECTIONS IN FISH”

Fin Dox (Doxycycline), 100 mg capsules, according to an image of the product label on your website:o “Antibiotics”o “FOR CONTROL OF COMMON BACTERIAL INFECTIONS IN FISH”

Fin Zole (Metronidazole), 250 mg tablets, according to an image of the product label on your website:o “Antibiotics”o “FOR CONTROL OF COMMON BACTERIAL INFECTIONS IN FISH”

Fin Pen (Penicillin), 250 mg and 500 mg tablets, according to images of the product labels on your website:o “FOR CONTROL OF COMMON BACTERIAL INFECTIONS IN FISH”

Aqua-Pen (Penicillin), 250 mg tablets, according to an image of the product label on your website:o “Controls common bacterial infections in FISH”

Fin Sulfa (Sulfamethoxazole/Trimethoprim), 960 mg tablets, according to an image of the product label on your website:o “Antibiotics”o “FOR CONTROL OF COMMON BACTERIAL INFECTIONS IN FISH”

These products are new animal drugs under section 201(v) of the FD&C Act [21 U.S.C. § 321(v)] because they are for use in nonfood-producing fish, which are minor species as defined by sections 201(nn) and (oo) of the FD&C Act [21 U.S.C. § 321(nn) and (oo)], and are not the subject of a final FDA regulation finding either that the drugs are generally recognized among experts qualified by scientific training and experience to evaluate the safety and effectiveness of animal drugs, as safe and effective for use under the conditions prescribed, recommended, or suggested in the drug’s labeling, or finding that the exception to the criterion in section 201(v)(1) of the FD&C Act has been met.

To be legally marketed, a new animal drug must be the subject of an approved new animal drug application, a conditionally approved new animal drug application, or a listing on the Index of Legally Marketed Unapproved New Animal Drugs for Minor Species (“index listing”) under section 512, 571, or 572 of the FD&C Act [21 U.S.C. § 360b, 360ccc, and 360ccc-1]. The FDA approval and index listing processes allow FDA to ensure that there is adequate evidence to demonstrate that new animal drugs are safe, properly manufactured, accurately labeled, and meet the relevant effectiveness standard. The animal drugs named above have not been approved, conditionally approved, or index listed.

Animal drugs that lack the required approval or index listing are considered unsafe and adulterated under sections 512(a) and 501(a)(5) of the FD&C Act [21 U.S.C. §§ 360b(a) and 351(a)(5)]. Introduction or delivery for introduction of an adulterated animal drug into interstate commerce is prohibited under section 301(a) of the FD&C Act [21 U.S.C. § 331(a)].

The FDA is particularly concerned about the marketing of these unapproved animal drugs because they contain antimicrobials considered medically important to human health.1 The growing threat of antimicrobial resistance, especially to drugs that are medically important in human medicine, has prompted FDA to promote judicious use of these drugs in animals. A key part of this effort is ensuring that these medically important antimicrobials are used only under the supervision of a licensed veterinarian. Over-the-counter use of these drugs without veterinary oversight contributes to the development of antimicrobial resistance, posing risks to both human and animal health.

Sections 510(b)(1) and (j)(1) of the FD&C Act [21 U.S.C. § 360(b), (j)] require that manufacturers (which includes repackers and relabelers) of drugs, including animal drugs, register their manufacturing establishments with FDA and provide the agency with a list of all the drug products they manufacture. Drugs that are manufactured in unregistered establishments or that have not been listed with FDA are misbranded under section 502(o) of the FD&C Act. None of the animal drugs in this letter are drug listed with FDA, nor have they been manufactured in a facility that is registered with FDA. Accordingly, these animal drugs are misbranded. Introduction or delivery for introduction of a misbranded animal drug into interstate commerce is prohibited under section 301(a) of the FD&C Act.

This letter is not intended to be an all-inclusive statement of violations that may exist in connection with your product(s). You are responsible for investigating and determining the causes of any violations and for preventing their recurrence or the occurrence of other violations. It is your responsibility to ensure that your firm complies with all requirements of federal law and FDA regulations.

This letter notifies you of our concerns and provides you an opportunity to address them. Failure to adequately address this matter may lead to legal or regulatory action, including without limitation, seizure and injunction.

You should be aware that if we take enforcement action against any of the drugs named above or other unapproved/unindexed products you market that contain medically important antimicrobials, we may take action against all of your products that violate the FD&C Act at the same time, including but not limited to enjoining the manufacturing and distribution of all of your unapproved/unindexed products.

We have the following comments:

1. You can legally market the products named above if you obtain an index listing, approval, or conditional approval. Information about the processes and requirements for obtaining an index listing and various types of animal drug approval is available on the FDA website at:

https://www.fda.gov/animal-veterinary/development-approval-process/minor-useminor-species and

https://www.fda.gov/animal-veterinary/development-approval-process/new-animal-drug-applications

The index listing process was added to the FD&C Act in 2004 as a streamlined alternative process that addresses the challenges of obtaining FDA approval for drugs for minor species (which are any animal species other than horses, cattle, pigs, dogs, cats, chickens, and turkeys). Drugs intended for use in minor species not used for human or animal food are eligible for index listing. Because the above-named products are intended for use in nonfood-producing fish, you may wish to explore the index listing process. The approval process can also be used for drugs for use in these species.

2. Information on establishment registration and drug listing is available on the FDA website at:

https://www.fda.gov/industry/fda-basics-industry/registration-and-listing

Your written response should be sent to the United States Food and Drug Administration, Center for Veterinary Medicine, Office of Surveillance and Compliance, Division of Drug Compliance, by emailing CVMUnapprovedDrugs@fda.hhs.gov.