Fish Flox (Fix Flox) Ciprofloxacin 500mg Capsules

Fish Flox (Fix Flox) is fish ciprofloxacin in 500 mg capsules from Aqua Soma Labs, for freshwater and saltwater aquarium fish. The label method is whole-tank dosing: one capsule per 10 gallons, added daily for 5 to 10 days.

Active ingredient

Ciprofloxacin

Strength

500 mg per capsule

Bottle sizes

30 or 60 capsules

Label dose

1 capsule per 10 gal (38 L)

Course

Daily for 5 to 10 days; stop if no improvement after day 5

Made by

Aqua Soma Labs, USA

When fish ciprofloxacin is the right call

Ciprofloxacin is a fluoroquinolone. It's strongest against gram-negative bacteria, the group behind many of the fastest, most destructive aquarium infections, including Aeromonas, Pseudomonas, and in marine tanks Vibrio. Penicillin-type antibacterials often struggle with these. Aquarists use Fish Flox when:

• Red ulcers deepen and widen from one day to the next
• Fin rot races toward the body, with bloody or white edges
• Pale, saddle-like patches or a frayed mouth spread through a group of fish
• Red streaking shows in the fins and under the skin along with lethargy
• A first course of amoxicillin or penicillin made no difference

Ciprofloxacin is a strong antibacterial, not a general tonic. Don't use it for parasites, fungus, or stress spots, and keep it for cases where a gram-negative infection is likely. For milder fin rot, Fish Mox is the gentler first step.

Fish Flox dosage by tank size

You'll find very different ciprofloxacin numbers online because some products are used as a short bath in a bucket rather than in the whole tank. Don't mix methods. This chart follows the Aqua Soma Labs whole-tank label; the label on your bottle comes first.

Dosing Fish Flox

1. Isolate. Gram-negative infections spread through shared water. Move the sick fish to a hospital tank and watch the rest of the group.
2. Strip the filter. Remove carbon, Purigen, and other resins, and turn off UV. Keep a sponge filter and add an air stone.
3. Dissolve. Open the capsules into a cup of tank water, stir until clear, and add it around the tank.
4. Daily routine. Water change first, then the full dose for the tank's volume, every 24 hours.
5. Day 5 decision. Ulcer edges should look less red and stop spreading. No improvement means stop, per the label.
6. Wrap up. Finish the course up to day 10 while the fish improve, then do a large water change and run fresh carbon.

30 or 60 capsules?

At one capsule per 10 gallons, Fish Flox uses more capsules than most of the line. A 10-day course in a 20 gallon tank takes 20 capsules, so a 30-count bottle covers one course with some spare. A 40 gallon tank needs 40 capsules, which calls for the 60-count bottle. From the 60-count bottle a 10-day course in 20 gallons costs about $28.30 at list price.

Where Fish Flox sits in the line

See all nine side by side on our fish antibacterials page.

Precautions

• Ciprofloxacin hits nitrifying bacteria hard. Treat in a hospital tank and test ammonia and nitrite daily.
• Calcium and magnesium bind it, so very hard water and crushed coral substrates reduce how much stays active.
• It breaks down under bright light. Keep the tank lights dim during the course.
• Never treat a tank with shrimp, snails, or corals.
• Don't combine Fish Flox with other treatments unless an aquatic veterinarian directs it.
• Store capsules sealed and dry, away from children and pets. Don't flush leftovers or treated water.

Fish Flox questions

Related guide: Ulcers and red sores on fish

For aquarium and ornamental fish only.