Ornamental aquarium fish, plus non-food pet birds under veterinary guidance
Manufacturer
Aqua Soma Labs
Prescription
No vet prescription required (over-the-counter)
Fix Flox (Fish Flox) Ciprofloxacin 500mg from Aqua Soma Labs is a pharmaceutical-grade, broad-spectrum fish and bird antibiotic for ornamental aquarium fish and non-food pet birds. Each capsule contains 500 mg of ciprofloxacin, a fluoroquinolone that interferes with bacterial DNA replication and can slow or stop the growth of susceptible gram-negative and some gram-positive bacteria in aquarium water when used as directed.
In the hobby it is still called Fish Flox, Fish Flox Forte, or Aqua Cipro. Fix Flox, from the Aqua Soma Labs Fix range, is the online replacement for the discontinued Thomas Labs Fish Flox and Aqua-Cipro 500 mg. Aquarists who used to buy fish cipro or a fish ciprofloxacin 500 mg capsule will recognize it as the same medication under a new label, and it is the only fluoroquinolone in the Fix lineup.
This over-the-counter (OTC) capsule helps with common bacterial problems: persistent fin and tail rot, columnaris-type patches, ulcer-like sores, red sores, hemorrhagic septicemia, swim bladder disease that involves bacteria, and dropsy-like swelling that is often linked to gram-negative organisms such as Aeromonas, Pseudomonas, Vibrio, or Flavobacterium. Reef keepers also use ciprofloxacin for anemone bacterial infections (deflating or "melting" anemones) in a separate hospital tank.
It comes in 30-count and 60-count bottles with fresh expiration dates, so you can buy the amount that fits your situation, whether that is a single hospital tank, several community aquariums, or ciprofloxacin for birds under avian veterinary guidance.
Start treatment early, at the first signs of bacterial stress. Those signs differ between fish and birds, so use the lists below to know what to watch for.
Fish-Specific Symptoms
Fin and tail rot (frayed or rotting fins)
Ulcer-like sores or open wounds
Red sores or red streaking on the body
Dropsy-like swelling
Columnaris-type patches
Cloudy patches that do not clear with better water quality
Lethargy, loss of appetite, or fast decline in activity
Bird Signs (Under Veterinary Guidance)
Fluffed-up feathers, lethargy, or inactivity
Decreased appetite
Loose or changed droppings
Labored or difficult breathing
Any sudden change a vet links to a bacterial problem
For birds, only use Fix Flox when an avian veterinarian has recommended ciprofloxacin for a specific problem and has set the dose. Catching a bacterial problem early, paired with stable water quality, good aeration, and suitable housing, gives your fish and birds the best chance to recover.
Order before 1:30 p.m. CT, Monday through Friday, and your order ships the same day 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 stayed the same:
Same Active Ingredient Fix Flox has the same 500 mg of ciprofloxacin per capsule you used in Fish Flox Forte and Aqua Cipro, and the pharmaceutical-grade formula works on the same bacteria.
New Manufacturer Fix Flox is made by Aqua Soma Labs, which replaced the discontinued Thomas Labs line and manufactures in the United States.
Same Capsule Form The capsule is the same format as the original Fish Flox, so it opens and dissolves in aquarium water the same way, or you can follow your vet's directions for birds.
Available in 30-Count and 60-Count Bottles Pick 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 and longer treatment courses.
Benefits of Fix Flox for Fish & Birds
Broad-Spectrum Fluoroquinolone Coverage
As a ciprofloxacin fish antibiotic, Fix Flox is generally described as effective against many gram-negative bacteria and some gram-positive ones. Aquarists use cipro fish antibiotics like Fix Flox for stubborn infections that may involve organisms such as Aeromonas, Pseudomonas, Vibrio, or Flavobacterium.
No Veterinary Prescription Required
Fix Flox is sold over the counter, so you can get cipro for fish without a vet prescription and buy fish antibiotics ciprofloxacin online with no prescription required to order. For birds, veterinary guidance is still strongly recommended to set the correct dose and duration.
Helps Manage Common Aquarium Bacterial Problems
As an aquarium ciprofloxacin treatment, Fix Flox is often chosen for stubborn fin rot, columnaris-type patches, bacterial gill irritation, ulcer-like sores, red streaking, hemorrhagic septicemia, or dropsy-like swelling tied to a bacterial infection. It is also used for anemone bacterial infections in a separate hospital tank.
Consistent 500 mg Capsules
Each capsule is a fixed 500 mg dose, which keeps dosing in a quarantine or hospital tank simple to calculate.
Easy to Administer
The capsule holds powder that opens and dissolves easily. Mix it in a small cup of aquarium water first, then spread it evenly around the treatment tank. The same method works for tanks of different sizes.
Versatile for Freshwater, Saltwater & Aviary Setups
Aquarists use Fix Flox in both freshwater and marine hospital tanks. For pet birds, give it only under avian veterinary guidance, when a vet decides it is appropriate for a serious bacterial problem.
Ideal for Hospital Tanks and Quarantine
A separate hospital tank protects your main aquarium's biofilter and keeps healthy tank mates away from the medication while you treat the fish that need it.
Dosage Guidelines & Instructions
Directions for Use: Always follow the directions printed on your bottle. The steps below cover the usual aquarium-water method for ornamental fish.
Set Up a Separate Treatment Area
Move affected fish to a dedicated hospital tank when you can. A separate tank makes dosing and observation easier and keeps the medication away from healthy tank mates and your main system's biofilter.
Prepare and Add the Dose
Open the capsule and dissolve the powder in a small cup of aquarium water, then spread it evenly around the treatment tank. Use one capsule (500 mg) per 10 gallons (38 L) of water you are treating.
Repeat and Maintain Water Quality
Repeat the dose every 24 hours. Do a partial water change between doses to keep ammonia and nitrite low, keep the aeration strong, and hold the tank stable. Continue daily dosing for 5 to 10 days.
Use in Pet Birds (Under Avian Veterinary Guidance)
Give this medication to pet birds only under the direction of an avian veterinarian. Do not use the aquarium-bath directions to dose a bird. Your vet will set the correct mg-per-kg dose, frequency, and duration for the species and condition.
Complete the Full Course
Finish the full course even if the fish look better, because stopping early can let the bacteria recover. If you see no improvement after 5 days, stop use as directed on the label and ask an aquatic professional for guidance.
Fix Flox Dosing by Aquarium Size
Tank volume
Ciprofloxacin per dose
500 mg capsules
10 gallons (38 L)
500 mg
1
20 gallons (76 L)
1000 mg
2
30 gallons (114 L)
1500 mg
3
40 gallons (151 L)
2000 mg
4
55 gallons (208 L)
about 2750 mg
5 to 6
These figures come from the label guideline of one 500 mg capsule per 10 gallons, about 50 mg per gallon. Dose by the water volume of your treatment tank, not by the number of fish, give one dose every 24 hours for 5 to 10 days, and round to the nearest practical capsule. The bottle label or your aquatic veterinarian takes priority over this quick-reference chart.
What to Expect During Treatment
Days 1 to 2
Fish may hide or eat less, and the water can look slightly cloudy. This is normal early on. Keep dosing on schedule and keep aeration strong.
Days 3 to 5
Look for signs it is working: sores and red patches stop spreading, appetite starts to return, and breathing steadies. If there is no change by day 5, or the fish look worse, stop and ask an aquatic veterinarian.
Days 5 to 10
Even if the fish are improving, finish the full course so the infection does not return. Afterward, run a partial water change and put activated carbon back in to clear any leftover medication.
What You Need for a Treatment Course
A little setup before the first dose saves trouble later.
A separate hospital or quarantine tank, so you are not medicating the whole display.
A heater and an air stone or sponge filter for steady temperature and strong aeration.
An ammonia and nitrite test kit to keep tabs on water quality.
A dechlorinator for the water changes between doses.
A small net and a clean cup for gentle transfer and measuring the dose.
Pro Tip: Quarantine sick fish away from healthy ones during treatment. A small hospital tank with a heater, an air stone, and no substrate makes dosing and water changes easier. Take out activated carbon and switch off UV sterilizers during treatment, since both can lower the medication level in the water.
How This Medication Works
Active ingredient: Ciprofloxacin (500 mg per capsule)
Ciprofloxacin is a fluoroquinolone antibiotic. It blocks bacterial DNA replication by acting on enzymes such as DNA gyrase and topoisomerase IV, which slows or stops the growth of susceptible bacteria when used as directed for ornamental fish. For pet birds, use it only under avian veterinary guidance.
Inactive ingredients
Capsule shell and filler materials that keep the active ingredient stable on the shelf and let the contents disperse properly once you dissolve them in aquarium water.
Side Effects & Safety Tips
When used as directed, this product is usually well tolerated in aquarium fish and non-food pet birds. As with any fluoroquinolone, the wrong dose or prolonged use raises the risk of side effects and antibiotic resistance.
Fish
Some fish may hide, eat less, act mildly lethargic, or the water may cloud temporarily during treatment. If a fish shows severe distress, such as rapid gill movement, loss of balance, gasping at the surface, or lying on the bottom, stop treatment, improve aeration, and get aquatic veterinary advice.
Birds
Give this medication to birds only under avian veterinary guidance. A bird may eat less, act lethargic, or pass loose or changed droppings, especially if it is sensitive or the dose is off. If your bird looks fluffed up, inactive, or stops eating, stop use and contact an avian veterinarian.
Invertebrates
Do not use Fix Flox in display tanks with shrimp, snails, or other invertebrates, since antibiotics can harm them or upset the tank ecosystem. Whenever you can, move affected fish to a separate hospital tank.
Safe use in your system
Treat fish in a hospital or quarantine tank whenever possible. Remove activated carbon and turn off UV sterilizers during treatment, and watch ammonia, nitrite, and temperature closely. Do not mix this product with other antibiotics unless a veterinarian tells you to.
Important safety warning
This product is for aquarium fish and non-food pet birds only. It is not for human use and not for animals raised for food. Taking fish or bird antibiotics instead of medicine prescribed for people can cause treatment failure, serious side effects, and antibiotic resistance. Store capsules in a cool, dry place away from direct sunlight, and keep them away from 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, and orders placed before 1:30 p.m. CT (Monday through Friday) ship the same day. For full details, see our shipping policy.
Refund Policy: If something is wrong with your order, you may be able to return or exchange items within 30 days under our store guidelines. Before you send anything back, please read 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 that aquarists use for bacterial problems such as persistent fin rot, columnaris-type patches, ulcer-like sores, red sores, hemorrhagic septicemia, and swim bladder disease in ornamental fish. For non-food pet birds, it may be used under avian veterinary guidance for serious bacterial concerns.
What is the difference between Fish Flox and Fix Flox?
Fish Flox was the brand name Thomas Labs used for its ciprofloxacin capsules. After Thomas Labs discontinued the product, Aqua Soma Labs introduced Fix Flox as a direct replacement. It has the same 500 mg of ciprofloxacin per capsule, the same capsule format, and the same ornamental-fish and pet-bird uses.
Is Fix Flox a replacement for Aqua Cipro?
Yes. If you used Aqua Cipro or Aqua-Cipro 500 mg before, Fix Flox from Aqua Soma Labs is a direct replacement with the same active ingredient (ciprofloxacin, 500 mg per capsule), and it comes in 30-count and 60-count bottles.
Is Fix Flox the same as Fish Flox Forte?
Fish Flox Forte was the name for the 500 mg ciprofloxacin capsule. Fix Flox from Aqua Soma Labs has the same 500 mg ciprofloxacin and replaces the Fish Flox Forte products that are no longer made.
What antibiotic is in Fix Flox (Fish Flox)?
Fix Flox contains ciprofloxacin, a fluoroquinolone antibiotic, at 500 mg per capsule. It is the same active ingredient that was in Thomas Labs Fish Flox and Fish Flox Forte. The capsule has no other active drug; the rest is inactive shell and filler material.
Is fish cipro the same as Fix Flox?
"Fish cipro" is a common nickname for ciprofloxacin sold as an aquarium antibiotic. Fix Flox is the current version: ciprofloxacin at 500 mg per capsule for ornamental fish and non-food pet birds. It is the same active ingredient for the same bacterial problems, just under a current label with fresh stock, and it replaces the older Thomas Labs fish ciprofloxacin and Aqua Cipro products.
Do I need a veterinary prescription to buy Fix Flox?
No. It is sold over the counter as a fish and bird antibiotic, so no veterinary prescription is needed to buy it. For pet birds, veterinary guidance is still strongly recommended to set the correct mg-per-kg dose and 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, by USPS or UPS.
How do I know if my fish might need a ciprofloxacin antibiotic?
Look 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 fast drop in activity or appetite. An aquatic veterinarian or an experienced aquarist can help confirm whether a bacterial infection is likely and whether ciprofloxacin is the right treatment.
What size aquarium can one Fix Flox capsule treat?
One capsule treats about 10 gallons (38 liters) of aquarium water. For a 20-gallon hospital tank, use two capsules per dose. Always dose by the actual water volume in the treatment tank, not the listed tank size, since gravel, decorations, and equipment take up space.
Can I use Fix Flox in my main community or reef tank?
It is better to treat sick fish in a separate hospital tank than in the main aquarium. This antibiotic is not recommended for reef tanks or tanks with shrimp, snails, corals, or other invertebrates, because antibiotics can harm them or disrupt the beneficial filter bacteria.
Does Fix Flox work in saltwater aquariums?
Yes. These capsules work in both freshwater and saltwater hospital tanks. Dissolve the contents at the standard dose (one capsule per 10 gallons) and keep salinity, temperature, and water quality stable through the full course.
How long should I treat with Fix Flox?
For fish, follow the label: one capsule per 10 gallons (38 L) once every 24 hours for 5 to 10 days, with a partial water change between doses. If there is no improvement after 5 days, stop use and ask an aquatic professional for guidance. Birds should get this medication only for the dose and duration an avian vet prescribes.
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 work out the correct mg-per-kg dose and decide whether treatment makes sense. Do not apply the aquarium-bath directions to a bird, and never guess a bird's dose or add capsules to shared water without professional guidance.
What bacteria does ciprofloxacin target in fish?
Ciprofloxacin is generally described as effective against many gram-negative bacteria, including organisms such as Aeromonas, Pseudomonas, Vibrio, and Flavobacterium, and against some gram-positive bacteria. It works by blocking DNA gyrase and topoisomerase IV, enzymes that bacteria need to copy their DNA.
Will Fix Flox harm beneficial aquarium bacteria?
Any broad-spectrum antibiotic can affect beneficial bacteria when used in the main tank. A hospital tank, regular checks of ammonia and nitrite, and partial water changes help protect the biofilter during treatment.
Should I remove carbon or turn off UV during treatment?
Yes. Activated carbon and UV sterilizers lower the medication level in the water. Remove carbon and other chemical filtration during the course, turn off the UV, keep aeration strong, and watch 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 usually not a good idea unless an aquatic veterinarian tells you to. Using several medications at once can stress fish, cause unpredictable interactions, and make it harder to tell which treatment is working.
Can Fix Flox treat fungal, viral, or parasitic infections?
No. This product works on certain bacterial infections only. It does nothing for fungi, viruses, or parasites such as ich, flukes, or worms. For a fungal, parasitic, or viral problem, work with an aquatic or avian veterinarian to pick the right treatment instead of using an antibiotic.
How should I store and dispose of Fix Flox capsules?
Store the capsules in their original container in a cool, dry place, away from heat, moisture, children, and pets. Follow local rules for disposing of medicine, and do not flush unused capsules down the drain unless local authorities tell you to.
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.
Tap image to expand & zoom 🔍
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.
See something that doesn’t match your bottle? Please contact us so we can review and update the page:
Contact Fine PetHealth.
Educational use: Our content is for informational purposes and is not a substitute for diagnosis or treatment from an aquatic or avian veterinarian.
Hey Jason! Thanks for leaving us 5 stars. We are thrilled to be able to provide you with the exact fish and bird antibiotics you need. Let us know whenever you need a restock for your pets!
S
Shawn Sheets (Phoenix, AZ)
Fix Flox 500-mg (Ciprofloxacin) Capsules Fish & Bird Antibiotics
