First-generation cephalosporin antibiotic — broad-spectrum treatment for gram-positive and gram-negative bacterial infections in ornamental fish. Why choose Cephalexin? Cephalexin is a first-generation cephalosporin — a class closely related to penicillin but with a broader and more resilient activity profile. It is an excellent alternative for fish that have not responded well to standard penicillin-class antibiotics, and is particularly effective at treating skin infections, open wounds, and ulcers. Also commonly known as Keflex, it is one of the most widely trusted broad-spectrum antibiotics in aquarium medicine. About This Product Cephalexin is a broad-spectrum, first-generation cephalosporin antibiotic effective against a wide range of gram-positive and gram-negative bacterial microorganisms. It works by disrupting bacterial cell wall synthesis, preventing bacteria from growing and replicating within the aquarium environment. Each capsule contains USP-grade cephalexin — available in 250mg and 500mg strengths, both in 100-capsule counts. As a cephalosporin, it offers a broader activity profile than standard penicillin, making it a reliable step-up option when penicillin-class treatments have not produced results. It is one of the most trusted antibiotics for treating bacterial skin infections, ulcers, and fin conditions in ornamental fish. Also commonly searched as: fish cephalexin, cephalexin for fish, keflex fish antibiotic, fish flex equivalent, aqua ceph equivalent, cephalosporin fish antibiotic. Commonly Treats Fin rot & tail rot Skin infections & body ulcers Open wounds & lesions Gill disease Bacterial hemorrhagic septicemia Dropsy Columnaris (mouth rot) Infections unresponsive to penicillin Directions for Use Determine your dose: Use one 250mg capsule per 10 gallons of water, or one 500mg capsule per 20 gallons of water. Dissolve the capsule in a small amount of aquarium water before adding to the tank. Stir until fully dissolved. Add directly to your aquarium, pond, or hospital/quarantine tank. Repeat every 24 hours for 5–10 days. Do not exceed 10 days of continuous treatment. Perform a 25% water change each day before re-dosing to maintain water quality and reduce antibiotic buildup. Product Specifications Active Ingredient Cephalexin USP Available Strengths 250mg · 500mg Available Counts 100 Capsules (both strengths) Form Capsule (dissolve before use) Antibiotic Class First-Generation Cephalosporin Spectrum Broad-spectrum (gram-positive & gram-negative) Tank Compatibility Freshwater & saltwater ornamental fish Prescription Required No Grade USP Pharmaceutical Expiration Typically 1–3 years from manufacture date Important Warnings & Cautions For ornamental fish use only. Not intended for use in fish raised for human consumption. Not for human consumption. Do not ingest. This product is sold for aquarium fish treatment only. Keep out of reach of children. Store in a cool, dry place away from children and pets. Do not exceed 10 days of continuous treatment. Overuse may contribute to antibiotic resistance in your aquarium ecosystem. Remove activated carbon from your filter before treatment — carbon will absorb the medication and render treatment ineffective. Label & Usage Disclaimer: Please read and follow all label directions before use. Product descriptions and usage instructions shown here are taken directly from the manufacturer’s product label and information provided by Montana Aquarium Supply. These statements do not represent the views or recommendations of Pittsboro Pet Supply or Pittsboro Feed. Made in the USA. Distributed by Montana Aquarium Supply – Billings, MT.
