Fix Flox 500 mg from Aqua Soma Labs is a trusted, pharmaceutical-grade, broad-spectrum fish and bird antibiotic capsule for ornamental aquarium fish and non-food pet birds. Each capsule supplies 500 mg ciprofloxacin, a fluoroquinolone antibiotic that targets bacterial DNA replication, helping slow or stop the growth of susceptible gram-negative and some gram-positive bacteria in aquarium water when used as directed.
Often called Fish Flox, Fish Flox Forte, or Aqua Cipro in the hobby community, Fix Flox from the Aqua Soma Labs Fix range serves as a reliable online alternative to discontinued Thomas Labs Fish Flox and Aqua-Cipro 500 mg products. Hobbyists searching for fish cipro, fish ciprofloxacin 500 mg, or a ciprofloxacin fish antibiotic will find Fix Flox is the dedicated fluoroquinolone option in the Fix lineup.
This over-the-counter (OTC) capsule helps manage common problems such as persistent fin and tail rot, columnaris-type patches, ulcer-like sores, red sores, hemorrhagic septicemia, swim bladder disease that may involve bacteria, and dropsy-like swelling often associated with gram-negative organisms (such as Aeromonas, Pseudomonas, Vibrio, or Flavobacterium). Reef keepers also reach for ciprofloxacin when treating anemone bacterial infections (deflating or "melting" anemones) in a separate hospital tank.
This product from Aqua Soma Labs is available to buy online in bottles of 30-count or 60-count capsules with fresh expiration dates, giving hobbyists flexible options whether they maintain a single hospital tank, multiple community aquariums, or need ciprofloxacin for birds under avian veterinary guidance.
Use this product when you notice early signs of bacterial stress such as persistent fin breakdown, worsening ulcers, red sores or red streaking, sudden dropsy-like swelling, rapid decline in activity or appetite in fish, or cloudy patches that do not respond to improved water quality alone. For pet birds, ciprofloxacin should be used only under the direction of an avian veterinarian when a severe bacterial concern is confirmed.
Addressing potential bacterial issues early, together with stable water quality, good aeration, suitable housing, and advice from an aquatic or avian professional when available, helps support a steadier, healthier aquarium or aviary.
Order online and enjoy same-day dispatch on orders placed before 1:30 p.m. CT, Monday through Friday. Fix Flox ships directly from our U.S. warehouse via USPS or UPS.
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.
Fish Flox vs Fix Flox: What Changed?
If you previously purchased Thomas Labs Fish Flox, Fish Flox Forte, or Aqua Cipro, here is what changed and what remains the same:
Same Active Ingredient Fix Flox contains the same 500 mg ciprofloxacin per capsule that you relied on with Fish Flox Forte and Aqua Cipro. The pharmaceutical-grade formulation targets the same bacteria.
New Manufacturer Fix Flox is made by Aqua Soma Labs, replacing the discontinued Thomas Labs line. Aqua Soma Labs manufactures in the United States under strict quality-control standards.
Same Capsule Form Fix Flox uses the same capsule format as the original Fish Flox, making it easy to open and dissolve the powder in aquarium water or follow veterinary directions for birds.
Available in 30-Count and 60-Count Bottles Choose the size that fits your setup: a 30-count bottle for a single hospital tank or occasional use, or a 60-count bottle for larger collections, multi-tank operations, or extended treatment courses.
Benefits of Fix Flox for Fish & Birds
Broad-Spectrum Fluoroquinolone Coverage
Fix Flox provides ciprofloxacin coverage commonly described as effective against many gram-negative and some gram-positive bacterial pathogens. Hobbyists reach for these capsules when dealing with persistent infections that may involve organisms such as Aeromonas, Pseudomonas, Vibrio, or Flavobacterium.
No Veterinary Prescription Required
Fix Flox is available over the counter for aquarium and avian use, so you can start treatment promptly without waiting for a prescription. For birds, professional veterinary guidance is still strongly recommended to determine the correct dose and duration.
Helps Manage Common Aquarium Bacterial Problems
Hobbyists often choose these capsules when dealing with stubborn fin rot, columnaris-type patches, bacterial gill irritation, ulcer-like sores, red streaking, hemorrhagic septicemia, or dropsy-like swelling that may accompany a bacterial infection. It is also highly regarded for treating anemone bacterial infections in a separate hospital tank.
Consistent 500 mg Capsules
Each capsule delivers a reliable 500 mg dose, making it easier to follow a structured treatment plan in a quarantine or hospital setup without complicated calculations.
Easy to Administer
The capsule contains powder that is easy to open and dissolve. Mix it in a small cup of aquarium water first, then distribute it evenly around the treatment tank. This format provides flexible dosing for tanks of different sizes.
Versatile for Freshwater, Saltwater & Aviary Setups
Hobbyists use Fix Flox in both freshwater and marine hospital tanks. For pet birds, this medication should be administered only under avian veterinary guidance when a veterinarian determines it is appropriate for severe bacterial concerns.
Ideal for Hospital Tanks and Quarantine
Using Fix Flox in a separate hospital tank helps protect the main aquarium's biofilter and reduces unnecessary exposure of healthy tank mates while you focus treatment where it is needed most.
Dosage Guidelines & Instructions
Directions for Use: Always follow the directions printed on your bottle. The steps below describe the typical aquarium-water dosing method for ornamental fish.
Set Up a Separate Treatment Area
Move affected fish to a dedicated hospital tank when possible. A separate setup makes dosing easier, improves observation, and helps reduce unnecessary exposure for healthy tank mates and the main system's biofilter.
Prepare and Add the Dose
Open the capsule and dissolve the powder in a small cup of aquarium water first, then distribute it evenly around the treatment tank. Use one capsule (500 mg) per 10 gallons (38 L) of water to be treated.
Repeat and Maintain Water Quality
Repeat the dose every 24 hours. Perform a partial water change between treatments to keep ammonia and nitrite low, maintain good aeration, and keep the treatment tank stable. Continue daily dosing for 5 to 10 days.
Use in Pet Birds (Under Avian Veterinary Guidance)
Only administer this medication to pet birds under the direction of an avian veterinarian. Do not use aquarium-bath directions to dose a bird. Your vet can advise the correct mg-per-kg dose, frequency, and duration for your species and condition.
Complete the Full Course
Continue treatment for the full recommended course even if fish appear better; stopping early can allow bacteria to recover. If no improvement is noted after 5 days, discontinue use per label and seek guidance from an aquatic professional.
Pro Tip: Always quarantine infected fish away from healthy companions during treatment. A small, dedicated hospital tank with a heater, air stone, and no substrate makes dosing and water changes easier. Remove activated carbon and turn off UV sterilizers during treatment, as they can reduce medication levels.
How This Medication Works
Active ingredient: Ciprofloxacin (500 mg per capsule)
Ciprofloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA replication by targeting enzymes such as DNA gyrase and topoisomerase IV. This helps slow or stop the growth of susceptible bacteria when used as directed for ornamental fish. For pet birds, use only under avian veterinary guidance.
Inactive ingredients
Capsule excipients and shell materials that help keep the active ingredient stable on the shelf and allow the contents to disperse properly when dissolved and distributed into aquarium water as directed.
Side Effects & Safety Tips
When used as directed, this product is generally well tolerated in aquarium fish and non-food pet birds. As with any fluoroquinolone, incorrect dosing or prolonged use can increase the risk of side effects and antibiotic resistance.
Fish
Some fish may show temporary stress or hiding behavior, reduced appetite, mild lethargy, or temporary water cloudiness during treatment. If fish show severe distress such as rapid gill movement, loss of balance, gasping at the surface, or lying on the bottom, stop treatment, improve aeration, and seek aquatic veterinary advice.
Birds
This medication for birds should be used only under avian veterinary guidance. Possible reactions can include reduced appetite, lethargy, or loose or changed droppings, especially if the bird is sensitive or the dose is not appropriate. If your bird appears fluffed up, inactive, or stops eating, discontinue use and contact an avian veterinarian.
Invertebrates
Do not use Fix Flox in display tanks that contain shrimp, snails, or other invertebrates, as antibiotics may harm them or disrupt the tank ecosystem. Whenever possible, move affected fish to a separate hospital tank.
Safe use in your system
Treat fish in a hospital or quarantine tank whenever you can. Remove activated carbon and turn off UV sterilizers during treatment, and monitor ammonia, nitrite, and temperature closely. Do not mix this product with other antibiotics unless advised by a veterinarian.
Important safety warning
This product is intended for aquarium fish and non-food pet birds only. It is not for human use and not for animals raised for food. Using fish or bird antibiotics in people instead of prescribed medicine can lead to treatment failure, serious side effects, and antibiotic resistance. Store capsules in a cool, dry place away from direct sunlight and keep out of reach of children and pets. Always follow the directions on the label.
Shipping & Returns
Shipping Policy: Orders ship from our U.S. warehouse within 1 business day via USPS or UPS, with same-day dispatch on orders placed before 1:30 p.m. CT (Monday through Friday). For full shipping details, please see our shipping policy.
Refund Policy: If there is 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
What is Fix Flox (Fish Flox) used for in fish and birds?
Fix Flox (ciprofloxacin 500 mg) is a fish and bird antibiotic used by hobbyists to help manage bacterial issues such as persistent fin rot, columnaris-type patches, ulcer-like sores, red sores, hemorrhagic septicemia, and swim bladder disease in ornamental aquarium fish. For non-food pet birds, it may be used under avian veterinary guidance for severe bacterial concerns.
What is the difference between Fish Flox and Fix Flox?
Fish Flox was the brand name used by Thomas Labs for their ciprofloxacin capsules. After Thomas Labs discontinued the product, Aqua Soma Labs introduced Fix Flox as a direct replacement. It contains the same 500 mg ciprofloxacin per capsule, uses the same capsule format, and is intended for the same ornamental fish and pet bird applications.
Is Fix Flox a replacement for Aqua Cipro?
Yes. If you previously used Aqua Cipro or Aqua-Cipro 500 mg, Fix Flox from Aqua Soma Labs is a direct replacement with the same active ingredient (ciprofloxacin 500 mg per capsule) and is available in 30-count and 60-count bottle sizes.
Is Fix Flox the same as Fish Flox Forte?
Fish Flox Forte was the name used for the 500 mg strength ciprofloxacin capsule. Fix Flox from Aqua Soma Labs contains the same 500 mg ciprofloxacin active ingredient and serves as a modern replacement for Fish Flox Forte products that are no longer manufactured.
Is Fix Flox a human Cipro alternative?
No. This product is not a human Cipro alternative. While it contains the same active ingredient, it is manufactured, packaged, and labeled strictly as an over-the-counter product for ornamental aquarium fish and non-food pet birds only. It is never a substitute for human medicine. Cipro is a registered trademark of Bayer.
Do I need a veterinary prescription to buy Fix Flox?
No. It is sold over the counter as a fish and bird antibiotic, and no veterinary prescription is required to purchase it. However, for pet birds, professional veterinary guidance is strongly recommended to determine the correct mg-per-kg dose and treatment duration.
Where can I buy ciprofloxacin for fish online?
You can buy these capsules directly from Fine Pet Health. Orders ship from our U.S. warehouse with same-day dispatch on orders placed before 1:30 p.m. CT, Monday through Friday, via USPS or UPS.
How do I know if my fish might need a ciprofloxacin antibiotic?
Watch for signs such as persistent fin breakdown, worsening ulcers, red sores or red streaking, sudden swelling, cloudy patches that do not improve with good water quality, or a rapid decline in activity or appetite. An aquatic veterinarian or experienced aquarist can help confirm whether a bacterial infection is likely and whether ciprofloxacin treatment is appropriate.
What size aquarium can one Fix Flox capsule treat?
One capsule treats approximately 10 gallons (38 liters) of aquarium water. For a 20-gallon hospital tank, use two capsules per dose. Always dose based on the actual water volume in the treatment tank, not the manufacturer-listed tank size, since gravel, decorations, and equipment reduce usable volume.
Can I use Fix Flox in my main community or reef tank?
It is best to treat sick fish in a separate hospital tank instead of the main aquarium. This antibiotic is not recommended for reef tanks or setups with shrimp, snails, corals, or other invertebrates, because antibiotics may harm them or disrupt beneficial filter bacteria.
Does Fix Flox work in saltwater aquariums?
Yes. These capsules can be used in both freshwater and saltwater hospital tanks. Dissolve the contents following the standard dosage (one capsule per 10 gallons) and maintain stable salinity, temperature, and water quality parameters throughout the treatment course.
How long should I treat with Fix Flox?
For fish, follow the label directions: one capsule per 10 gallons (38 L) once every 24 hours for 5 to 10 days, with a partial water change between treatments. If no improvement is noted after 5 days, discontinue use and seek guidance from an aquatic professional. Birds should only receive this medication for the dose and duration prescribed by an avian vet.
Is Fix Flox safe for pet birds?
These capsules can be used in pet birds only under the direction of an avian veterinarian, who will calculate the correct mg-per-kg dose and decide whether treatment is appropriate. Do not apply aquarium-bath directions to a bird. Never guess bird dosages or add capsules to communal water without professional guidance.
What bacteria does ciprofloxacin target in fish?
The active ingredient is commonly described as effective against many gram-negative bacteria, including organisms such as Aeromonas, Pseudomonas, Vibrio, and Flavobacterium, and some gram-positive organisms. It works by inhibiting bacterial DNA gyrase and topoisomerase IV, which are enzymes essential for DNA replication.
Will Fix Flox harm beneficial aquarium bacteria?
Any broad-spectrum antibiotic can affect beneficial bacteria if used in the main tank. Using a hospital tank, monitoring ammonia and nitrite, and performing partial water changes helps protect the biofilter while treatment is underway.
Should I remove carbon or turn off UV during treatment?
Yes. Activated carbon and UV sterilizers can reduce medication levels in the water. Remove carbon and other chemical filtration media and turn off UV during the treatment course. Maintain strong aeration and monitor ammonia and nitrite closely.
Can I combine Fix Flox with other fish medications?
Combining antibiotics or mixing these capsules with antifungal or antiparasitic medications is generally not recommended unless specifically advised by an aquatic veterinarian. Using multiple medications at once can stress fish, cause unpredictable interactions, and make it harder to identify which treatment is working.
How quickly should I see improvement?
Many aquarists notice reduced redness, improved fin condition, and more normal swimming or appetite within a few days once water quality is stable and the full course is followed. If fish fail to improve or seem worse after several days, stop treatment and seek aquatic veterinary advice.
Can Fix Flox treat fungal, viral, or parasitic infections?
No. This product targets certain bacterial infections only. It is not effective against fungi, viruses, or parasites such as ich, flukes, or worms. For fungal, parasitic, or viral problems, work with an aquatic or avian veterinarian to choose an appropriate treatment instead of using an antibiotic.
How should I store and dispose of Fix Flox capsules?
Store capsules in their original container in a cool, dry place away from heat, moisture, children, and pets. Follow local guidelines for pharmaceutical disposal and avoid flushing unused capsules down the drain unless specifically instructed by local authorities.
More Fish & Bird Antibiotics
Fix Mox (Amoxicillin) 250/500mg A broad-spectrum penicillin-type fish antibiotic for fin rot, dropsy, ulcers and other bacterial infections. Available in 30-count and 100-count capsules. Shop Fix Mox Amoxicillin
Fix Zole (Metronidazole) 250/500mg Targets anaerobic bacteria and protozoa including Hexamita and hole-in-the-head disease in ornamental fish. Available in 60-count bottles. Shop Fix Zole Metronidazole
Fix Doxy (Doxycycline) 100mg A tetracycline-class fish and bird antibiotic effective against columnaris, respiratory infections and Mycoplasma. Available in 30-count and 60-count tablets. Shop Fix Doxy Doxycycline
Fix Zithro (Azithromycin) 250mg A macrolide fish and bird antibiotic for fin rot, columnaris, gill disease and avian respiratory concerns. Available in 12-count and 30-count tablets. Shop Fix Zithro Azithromycin
Fix Cin (Clindamycin) 150mg A lincosamide fish antibiotic commonly used for gram-positive bacterial infections including skin and soft tissue concerns in ornamental fish. Shop Fix Cin Clindamycin
Fix Sulfa (SMZ/TMP) 960mg A sulfonamide combination fish antibiotic offering broad-spectrum coverage against a range of bacterial infections in ornamental fish. Shop Fix Sulfa SMZ/TMP
Fix Pen (Penicillin) 500mg A penicillin-type fish and bird antibiotic for gram-positive bacterial infections in ornamental fish and non-food pet birds. Shop Fix Pen Penicillin
Fix Flex (Cephalexin) 250/500mg A first-generation cephalosporin fish and bird antibiotic for fin rot, ulcers and bacterial skin infections in ornamental fish. Shop Fix Flex Cephalexin
Guides and treatment tips Visit the Fish & Bird Antibiotics Blog for practical dosing guides, water-care advice and treatment tips.
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About Fine PetHealth and How We Verify Our Antibiotic Guides
Who is responsible for this page: Fine PetHealth Editorial Team.
Verification snapshot: This guide is written from the current product label for this item and reviewed for accuracy and consistency before publishing.
How we verify product information (our checklist):
1) Label-first accuracy: Dosing, duration, storage, and warnings are taken from the current product label for this item.
2) Ingredient validation: Active ingredient names are cross-checked against reputable references (for example, NIH PubChem) to reduce the risk of labeling mistakes.
3) Consistency checks: We review for internal consistency (the same dosing and storage language across sections) and remove wording that could overpromise results.
4) Updates: We update pages when label directions, packaging, or manufacturer information changes.
What we don’t do: We don’t invent diagnoses, and we don’t create dosing instructions beyond what the product label states for this item’s intended use.
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Educational use: Our content is for informational purposes and is not a substitute for diagnosis or treatment from an aquatic or avian veterinarian.
