Fix Mox (Fish Mox) Amoxicillin Capsules for Fish & Birds – 250 mg / 500 mg
Fix Mox (also known as Fish Mox) is a broad-spectrum amoxicillin antibiotic in capsule form for aquarium fish and pet birds. This convenient fish antibiotic helps treat common bacterial problems like Dropsy (bloating), Fin & Tail Rot, Red Pest, Gill Disease and Skin Ulcers in both freshwater and saltwater aquariums. The capsules dissolve quickly in the water so the medication spreads evenly through the tank and reaches stressed or hiding fish.
Amoxicillin works by blocking bacterial cell wall formation, helping stop the infection from spreading and reducing the risk of severe complications such as septicemia. It is active against many gram-positive and gram-negative bacteria, including Aeromonas and Pseudomonas. With 250 mg and 500 mg strengths, Fix Mox lets you match the dose to your tank size and the severity of the problem.
Important Notice: This product is intended for aquarium and ornamental fish and pet birds only. It is not for human consumption or for animals used for food. We do not sell or recommend this product for human use.
Use Fix Mox when you notice signs like lethargy, bulging eyes, red streaks, open sores or rapid breathing. Targeting bacterial infections early with amoxicillin helps your fish and birds recover faster and supports a healthier aquarium or aviary environment.
Looking for an all-in-one fish antibiotic?
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Covers key fish and bird infections
Helps manage Dropsy (bloating), Fin and Tail Rot, Ulcers, red streaks, Gill Disease, respiratory infections and Pop-eye in aquarium fish and pet birds.
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Broad-spectrum amoxicillin formula
Targets a wide range of Gram-positive and Gram-negative bacteria, including Aeromonas and Pseudomonas, helping stop infection spread before it becomes severe.
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Flexible 250 mg and 500 mg dosing
Choose 250 mg or 500 mg capsules to match your tank size, stocking level or bird flock and the severity of the infection.
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Easy-to-use capsules for tanks and feed
Capsules dissolve quickly in tank water for fish or can be opened and mixed with feed for birds, minimizing handling stress.
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Smart alternative to discontinued Fish Mox
Amoxicillin capsules from Aqua Soma Labs that many hobbyists now use as a Fish Mox replacement for bacterial issues in ornamental aquarium fish.
How to dose Fix Mox amoxicillin for aquarium fish and pet birds
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Prepare the tank
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Remove activated carbon and UV sterilizers from the filter so they do not strip the antibiotic from the water.
- Perform a partial water change (about 20–25%) before starting treatment.
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Choose the right capsule strength
- Use 250 mg capsules for smaller tanks and milder cases.
- Use 500 mg capsules for larger tanks or more severe bacterial infections.
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Dosage and administration
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For fish: Dose at approximately 250 mg per 10 gallons or 500 mg per 20 gallons of aquarium water. Sprinkle the capsule contents directly into the tank and repeat every 24 hours.
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For birds: Open the capsule and mix the contents thoroughly with a small amount of feed or drinking water so the full dose is taken. Whenever possible, follow your avian veterinarian’s specific dosing guidance.
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Treatment length
- Continue treatment for 5–10 days, even if symptoms start to improve sooner, unless your veterinarian advises otherwise.
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After the course
- Perform a partial water change and then replace activated carbon or other chemical media to remove any remaining medication and help restore water clarity and biological balance.
For best results, monitor your fish or birds closely during treatment and consult an aquatic or avian veterinarian if symptoms do not improve or if you are unsure about dosing.
What is the active ingredient in Fix Mox?
Active ingredient: Amoxicillin Trihydrate
Each capsule contains 250 mg or 500 mg of amoxicillin, a broad-spectrum beta-lactam antibiotic used for bacterial problems in aquarium fish and pet birds. Amoxicillin interferes with bacterial cell wall formation, helping control susceptible Gram-positive and Gram-negative bacteria such as Aeromonas and Pseudomonas that are linked with fin rot, tail rot, columnaris, dropsy and other common infections when used as directed.
Fix Mox side effects, precautions and storage
Potential side effects: As with any amoxicillin fish antibiotic, some fish or birds may show mild digestive upset, temporary loss of appetite or lethargy during treatment. If symptoms worsen or new signs appear, stop using Fix Mox and consult an aquatic or avian veterinarian.
Precautions: For aquarium and ornamental fish and pet birds only. Do not use in animals intended for food. Keep out of reach of children and other household pets.
Storage: Store Fix Mox capsules in a cool, dry place at 59°–86°F (15°–30°C), away from moisture and direct sunlight, with the container tightly closed.
Shipping & Returns
Shipping Policy: Orders ship from our U.S. warehouse within 1 business day via USPS or UPS, with rates and delivery times calculated at checkout. For full shipping details, please click here.
Refund Policy: If there’s an issue with your order, you may be able to return or exchange items within 30 days according to our store guidelines. Before sending anything back, please review our refund policy carefully.
Frequently asked questions about Fix Mox (amoxicillin) for fish and birds
Does Fix Mox help with dropsy and pop-eye?
Yes. Fix Mox contains amoxicillin, a broad-spectrum antibiotic that is often used when bacterial infections cause signs such as Dropsy (swollen body), Pop-eye (bulging eyes), lethargy, fin and tail damage or open sores in ornamental fish.
Is Fix Mox the same as Fish Mox or Aqua Mox?
Fix Mox is an amoxicillin-based fish antibiotic similar to discontinued products sold as “Fish Mox” or “Aqua Mox.” It uses the same type of active ingredient for similar aquarium bacterial problems but is a different brand, so always follow the Fix Mox label directions.
Do I need a prescription to buy Fix Mox?
Fix Mox is sold as an over-the-counter amoxicillin fish antibiotic for aquarium fish and pet birds in many regions. However, it does not replace professional veterinary care, and you should always follow local regulations and consult an aquatic or avian veterinarian for serious or recurring problems.
Can Fix Mox be used in saltwater tanks?
Yes. Fix Mox amoxicillin capsules can be used in both freshwater and saltwater aquariums when dosed correctly. Monitor water quality closely during treatment and make partial water changes as needed.
How long should I treat my fish or bird with Fix Mox?
Most courses last 5–10 days. Unless your veterinarian advises otherwise, continue for the full course even if symptoms start to improve sooner, and stop if you see worsening signs or unusual reactions.
Is Fix Mox safe for invertebrates like shrimp and snails?
Fix Mox is not specifically formulated or tested for invertebrates. To protect sensitive species such as shrimp, snails and some live plants, we recommend treating sick fish in a separate quarantine tank rather than in a display aquarium.
Will Fix Mox affect beneficial bacteria in my aquarium?
Any broad-spectrum antibiotic can impact beneficial bacteria to some degree. While Fix Mox primarily targets harmful bacteria, you should watch ammonia and nitrite levels during and after treatment and consider re-seeding the filter or adding a bacterial supplement once the course is finished.
Can I combine Fix Mox with other medications?
Avoid combining Fix Mox with other fish medications, especially additional antibiotics, unless an aquatic or avian veterinarian specifically recommends it. Mixing treatments can stress fish and change water chemistry.
Is Fix Mox the same amoxicillin humans take?
No. Fix Mox is formulated and packaged for aquarium fish and pet birds only and has not been evaluated or approved for human use. It must never be used as a substitute for human medication.
Explore More & Stay Informed
Ready to see additional OTC fish antibiotics or bird solutions? Check out our
Fish & Bird Antibiotics Collection for a wide selection of products.
Curious about best practices, dosing schedules, or success stories? Visit our
Fish & Bird Antibiotics Blog to stay informed and give your pets the care they deserve.
