Fish Mox

How Much Does Fish Mox Cost?

$9.99 for the Fish Mox Thomas Labs Fish Mox Amoxicillin Antibacterial Fish Medication, 250 mg.

The cheapest price for any Fish Mox product is $9.99 for Fish Mox Thomas Labs Fish Mox Amoxicillin Antibacterial Fish Medication, 250 mg at The highest price found is $15.99. Pricing was updated at 1:29 pm Wednesday, March 4th.

Where to buy Fish Mox

Fish Mox has 2 product variation(s). It is available from 4 online store(s), including: | | |

Product Price
Thomas Labs Fish Mox Amoxicillin Antibacterial Fish Medication, 250 mg $9.99 View on
Thomas Labs Fish Mox Forte Amoxicillin Antibacterial Fish Medication, 500 mg $15.99 View on

Best Prices for Fish Mox Products(s)

Fish Mox

Fish Mox is the brand name of a pharmaceutical-grade antibiotic, amoxicillin, that is intended to be used to treat diseases of fish kept in aquariums.

How to use

Fish Mox comes in capsules, each containing 250 mg of amoxicillin. It comes in bottles with 30, 60, or 100 capsules. Amoxicillin is a broad-spectrum antibiotic effective against most bacteria, including most Gram-positive and some Gram-negative bacteria.

One 250 mg capsule per 10 gallons of water should be added to the aquarium. Twenty-four hours later, a 20% water change should be performed, and then a fresh dose of amoxicillin should be applied. Repeat this regimen for five days and then carefully observe the fish. If they seem to be improving, continue with the regimen for a full ten days; if they do not noticeably respond within the first five days, discontinue treatment and reconsider the original diagnosis. It is vital to complete the full ten-day treatment regimen even if the fish appear completely healed before reaching ten days.

This medication will add a harmless yellow tint to the water. After completing treatment, water changes and charcoal filtration will remove the tint.

Fish Mox is commonly used to treat fin and scale rot, skin ulcerations, columnaris disease, eye infections, popeye, gill diseases, and other conditions caused by bacterial infections.


Popeye is a condition characterized by a fish having a bulging, swollen, cloudy eye. One or both eyes can be affected. If only one eye on one fish in the tank is affected, the condition is probably caused by an injury and will not respond to amoxicillin treatment. However, if multiple eyes in the aquarium are affected, there is likely to be a bacterial infection spreading through the tank, and amoxicillin treatment is indicated.


A fish with an enlarged, bloated abdomen may have a condition called dropsy. As the condition progresses, skin ulcers may form, and the fish will become very sluggish. Dropsy has a poor prognosis, and most affected fish die unless they receive treatment during the very early stages of the condition. This disease is caused by infection with a Gram-negative bacterial species. If the condition is advanced, the fish should be euthanized, and the tank treated with amoxicillin to protect the other fish. If the disease is caught in the early stages, the affected fish should be isolated and treated with amoxicillin, and the home tank should also be treated with amoxicillin.


Columnaris commonly affects live-bearing fish like guppies and mollies, and also affects catfish. It produces white skin lesions on the head, around the gills, and down the back that look like they are caused by a fungus or mold, but a bacterial infection causes this disease and it responds readily to amoxicillin treatment of the tank.

Conditions that amoxicillin cannot treat