Aquarium fish antibiotics
Fish Cipro: Ciprofloxacin for Fish (500 mg Tablets, 30 Count)
A gram-negative fluoroquinolone for ornamental fish. Intended for aquarium fish only, not for human use.
These images are for illustrative purposes only.
Delivery in 10–14+ business days. Restock your aquarium’s medicine shelf before your fish need it. This is for planning ahead, not same-day treatment.
No public checkout. After you place an order, our pharmacy confirms your address and sends a secure payment link. A qualified team member reviews every order for aquarium use before it ships. Your card isn’t charged until you approve the link.
New here? See how our free vet prescription works. You pay only for the medication; a licensed vet must approve it first. A licensed vet reviews every order, with no separate consult fee.
Quick answer: Fish cipro is ciprofloxacin for fish. It is a fluoroquinolone that targets gram-negative infections such as Aeromonas and Pseudomonas. The bacteria behind many ulcers, fin rot, and dropsy-type cases. A fish vet should confirm the cause; drug choice and dose are the vet’s call, ideally guided by testing. For aquarium fish only; not for human use.
Not sure of your tank size? Use our free aquarium tank volume calculator to get the true water volume for accurate dosing.
Starting a course? Use our antibiotic treatment tracker to log each dose, stay on schedule, and know when it’s time to call the vet.
What fish cipro is
Fish cipro is the common name for ciprofloxacin sold for aquarium fish. Ciprofloxacin is a fluoroquinolone, an antibiotic that works especially well against gram-negative bacteria. This product is the same molecule, manufactured and labeled specifically for ornamental fish.
We are a licensed, vet-staffed pharmacy, not a repackager. Our job is to sell you the right treatment, and to help you use ciprofloxacin for the right reason. A vet confirms the cause and the dose. That care is the whole point.
| Active ingredient | Ciprofloxacin (as hydrochloride) |
|---|---|
| Strength | 250 mg or 500 mg per tablet |
| Count | 100 tablets |
| Drug class | Fluoroquinolone |
| Form | Capsules sealed in blister packs, open for tank dosing |
| Intended use | Ornamental / aquarium fish only |
| Availability | Over-the-counter for aquarium use only, not for human consumption |
| Delivery to | Free to all 50 US states & Canada, other countries, contact us |
Why blister packs, not a bottle
Each capsule is sealed in its own aluminum foil pocket, backed by foil on both sides. That keeps every dose away from moisture and light until you use it. This matters for ciprofloxacin, which is sensitive to light and moisture.
A bottle is different. Every time you open it, the tablets still inside meet air, light, and humidity again. Sealed pockets also make tampering easy to see, and U.S. regulators count blister packs as tamper-evident. Blister packs cost us more than bulk bottles. The protection is worth it.
What it treats. And what it doesn’t
Where ciprofloxacin can help
Ciprofloxacin is a strong choice against gram-negative bacteria.1 Those are the bacteria behind many of the worst aquarium infections, Aeromonas and Pseudomonas, which drive ulcers, fin rot, and the kind of body swelling people call dropsy.2 When a fish vet confirms a gram-negative infection, ciprofloxacin is often one of the most effective options, because it stops bacteria from copying their DNA.3 The drug and dose remain the vet’s decision, guided by testing.
Where it’s the wrong choice
Ciprofloxacin doesn’t treat viral, fungal, or parasitic problems. Using a powerful antibiotic when it’s not needed drives resistance. And fluoroquinolones are a class worth protecting, not reaching for by default.3 A vet should confirm the cause and, where possible, test which antibiotic fits, rather than starting the strongest drug on a guess.
Take care with your tank: like most antibiotics, ciprofloxacin can harm the good bacteria in your filter, so watch your water closely during treatment. Remove activated carbon first, because it pulls the medicine out of the water. And a fish vet should confirm the cause before you treat.
Fish cipro strengths and label rates by tank volume
Fish cipro is sold as ciprofloxacin tablets, commonly 250 mg and 500 mg. The same product also sold as Fish Flox, Aqua Cipro, or Fishbiotic Ciprofloxacin (Thomas Labs brand names now largely discontinued). The quick-reference below scales a common manufacturer’s label rate of about 250 mg per 10 gallons to typical tank sizes. It is the label rate for planning, not a prescription. Your fish veterinarian sets the actual dose, frequency, and duration, and fluoroquinolones like cipro deserve careful, confirmed use rather than a first guess.
| Tank volume | Label rate (ciprofloxacin) | 250 mg tablets | 500 mg tablets |
|---|---|---|---|
| 10 gallons (38 L) | 250 mg | 1 | — |
| 20 gallons (76 L) | 500 mg | 2 | 1 |
| 40 gallons (151 L) | 1000 mg | 4 | 2 |
| 60 gallons (227 L) | 1500 mg | 6 | 3 |
Dose by the water volume of your hospital or quarantine tank, not by the number of fish, and pre-dissolve each tablet. The bottle label and your aquatic veterinarian always take priority over this quick reference. Because resistance to fluoroquinolones is a serious concern, cipro is best reserved for cases a vet has confirmed rather than used first by default.
Not for human use. This product is for aquarium fish only. It isn’t approved for people. Do you want to know if fish antibiotics are safe for humans? Please read our guidance. Then talk to a doctor. Do not take this product.
How your order is reviewed and shipped
Add the quantity you need to the cart (1–12). Instead of a public checkout, our pharmacy emails you to confirm your delivery address and send a secure payment link. Nothing ships until that review is complete. It is how a vet-staffed operation keeps eyes on every order and confirms it’s intended for appropriate aquarium use. We email you at each step, reserved, confirmed, payment link sent, paid, and shipped. So you never have to sit and refresh a page.
GETTING THE MOST FROM AN ANTIBIOTIC
Antibiotics work on bacterial infections, not viruses — so the first step is simply confirming that’s what your pet has. That’s what the vet review here is for: matching the right antibiotic to the actual problem, at the right dose. This one is broad-spectrum, so a vet will typically save it for infections where a more targeted antibiotic wouldn’t do the job.
If a course is prescribed, giving all of it as directed — rather than stopping early once your pet looks better — is what fully clears the infection and keeps the medicine working well for next time. You clearly want to do right by your animal; this is just the way to get the best result from it.
Consistent with WHO and CDC guidance on responsible antibiotic use.
Frequently asked questions about fish cipro
What does fish cipro treat in fish?
Ciprofloxacin is a fluoroquinolone that works well against gram-negative bacteria such as Aeromonas and Pseudomonas, behind many ulcers, fin rot, and dropsy-type cases. A fish vet should confirm the cause and choose the drug and dose, ideally guided by testing.
Is fish cipro safe for humans?
No. This product is for ornamental aquarium fish only and isn’t for human use. If you need antibiotics for a person, see a doctor or pharmacist. You can read our guidance on this.
Is fish cipro the same as human ciprofloxacin?
The active ingredient is the same molecule, but this product is manufactured, labeled, and sold for ornamental aquarium fish only, and isn’t intended or approved for human use.
Do I need a prescription?
This is an over-the-counter product for aquarium use. After you add it to the cart, our pharmacy confirms your delivery details and sends a secure payment link before anything ships.
Should I remove carbon from my filter?
Yes. Activated carbon absorbs the medicine and makes it much weaker. Remove it before treating, and ask a fish vet about protecting your filter’s good bacteria.
Is fish cipro the same as Fish Flox, Aqua Cipro, or Fishbiotic Ciprofloxacin?
They are the same active drug under different brand names. Fish Flox, Aqua Cipro, and Fishbiotic Ciprofloxacin (Thomas Labs brands, now largely discontinued) all supplied ciprofloxacin for aquarium use. Strength and count differ between brands, so dose from the label on the bottle you actually have.
Does fish cipro come in 250 mg and 500 mg?
Yes, ciprofloxacin for fish is commonly sold as 250 mg and 500 mg tablets. Match the strength to your hospital-tank volume using the label-rate table above, and let your aquatic vet confirm.
Where can I buy ciprofloxacin for fish, do Walmart or Tractor Supply sell it?
General retailers don’t reliably carry aquarium ciprofloxacin. A dedicated vet-staffed pharmacy is the more reliable route, with clear strength labels and fresh stock. You can reserve it here and our pharmacy confirms your order before it ships.
Related guides
Columnaris. The fast-moving gram-negative disease ciprofloxacin is often chosen for once a vet confirms it; speed matters.
Fin rot. A common gram-negative infection where a fluoroquinolone like cipro may fit severe or resistant cases.
Fish dropsy. A gram-negative infection where ciprofloxacin is one of the drugs a vet may choose.
Fish popeye. The bulging-eye sign, its causes, and when antibiotics help.
Are fish antibiotics safe for humans?. A clear, no-sales answer.
How we reviewed this page
This product page is prepared under veterinary oversight following our editorial standards. The clinical statements, what ciprofloxacin treats and where it’s not the right choice, are checked against aquatic-veterinary references and reviewed and approved by our named fish veterinarian, Dr. Julia Bauer, before publication.
Sources & References
- Merck Veterinary Manual, “Bacterial Diseases of Fish.” merckvetmanual.com (2024) Supports: gram-negative etiology of common fish infections; sensitivity-guided drug selection.
- MSU / SRAC Publication 478, “Aeromonas Bacterial Infections, Motile Aeromonad Septicemia.” srac.msstate.edu (1998) Supports: aeromonads are gram-negative; exophthalmia and related signs.
