Fish Mox (Amoxicillin 500mg) is a broad-spectrum antibiotic capsule trusted by aquarium fish keepers for treating serious bacterial infections in freshwater and saltwater ornamental fish. Each capsule contains 500mg of Amoxicillin — a penicillin-class antibiotic that disrupts bacterial cell wall synthesis, stopping harmful bacteria from reproducing and spreading throughout your tank.
Whether you are dealing with fin rot, dropsy, bacterial gill disease, skin ulcers, open sores, or internal bacterial infections, Fish Mox delivers fast-acting, reliable coverage against both gram-positive and gram-negative aquatic pathogens. Its water-soluble formula dissolves quickly and distributes evenly throughout your aquarium, ensuring your fish receive consistent and effective treatment from the first dose.
Fish Mox is intended for ornamental and aquarium fish use only and is available at CalVetSupply without a vet prescription — so you can identify the problem and start treatment without delay.
KEY BENEFITS
- Broad-Spectrum Coverage — Targets both gram-positive and gram-negative bacteria responsible for the most common aquarium fish infections
- Fast Dissolving Formula — Dissolves quickly in tank water for even distribution and rapid absorption
- Treats Internal & External Infections — Effective for both surface-level conditions like fin rot and ulcers as well as internal infections like dropsy and bacterial septicemia
- Prevents Infection Spread — Inhibits bacterial cell wall synthesis to halt progression before infections become life-threatening
- No Prescription Required — Available for ornamental fish use without a vet visit at CalVetSupply
WHAT DOES FISH MOX TREAT?
Fish Mox (Amoxicillin 500mg) is effective against the following bacterial conditions in ornamental aquarium fish:
- Fin rot & tail rot
- Dropsy (swollen abdomen)
- Bacterial gill disease
- Skin ulcers & open sores
- Red streaks in fins
- Bulging eyes (popeye)
- Internal bacterial infections
- Bacterial septicemia
- Aeromonas & Pseudomonas infections
ACTIVE INGREDIENT
Amoxicillin 500mg per capsule
DOSAGE & DIRECTIONS
- Remove activated carbon from your filter before starting treatment
- Dissolve one capsule (500mg) per 20 gallons of tank water
- Repeat treatment every 24 hours
- Continue treatment for a minimum of 5 days and no longer than 10 days
- Perform a partial water change between treatments
- After completing the full course use a carbon filter to clear residual medication from the water
Important: Always complete the full treatment course even if symptoms improve early. Stopping treatment prematurely can lead to antibiotic resistance and relapse.
WHEN TO USE FISH MOX
Use Fish Mox when your ornamental fish shows one or more of the following symptoms:
- Lethargy or reduced movement
- Torn, frayed, or disintegrating fins
- Red streaks or bloody patches on fins or body
- Open sores, ulcers, or wounds on the skin
- Swollen or bloated abdomen
- Bulging eyes
- Rapid or labored gill movement
Note: Confirm that symptoms are caused by a bacterial infection rather than a parasitic or fungal condition before administering Fish Mox. If unsure consult an aquatic veterinarian before treatment.
PRECAUTIONS & SAFETY
- For ornamental aquarium fish use only
- Not for use with fish intended for human consumption
- Remove activated carbon before treatment
- Fish Mox may slightly affect beneficial bacteria in your tank — consider using aquarium probiotics after completing treatment to restore biological balance
- Not specifically tested for invertebrates — consult an aquatic veterinarian before use in tanks with shrimp or snails
- Keep out of reach of children and pets
- Store in a cool dry place between 59°F and 86°F (15°C–30°C) with lid tightly closed
FAQ
Q: What bacterial infections does Fish Mox treat?
A: Fish Mox treats fin rot, dropsy, bacterial gill disease, skin ulcers, open sores, popeye, internal bacterial infections, and Aeromonas and Pseudomonas infections in ornamental aquarium fish.
Q: Do I need a prescription to buy Fish Mox?
A: No. Fish Mox is available at CalVetSupply without a vet prescription for ornamental aquarium fish use only.
Q: Can Fish Mox be used in saltwater tanks?
A: Yes. Fish Mox can be used in both freshwater and saltwater aquariums. Always follow label dosage directions for correct treatment.
Q: How long does Fish Mox treatment take?
A: Treat for a minimum of 5 days and no longer than 10 days. Always complete the full course even if your fish recovers early.
Q: Will Fish Mox harm my tank's beneficial bacteria?
A: Fish Mox may slightly affect beneficial bacteria. Use aquarium probiotics after completing treatment to help restore your tank's natural bacterial balance.
Q: Can Fish Mox be used for fry or juvenile fish?
A: Yes with careful dosing and close monitoring. Ensure correct dosage per gallon and observe juvenile fish closely throughout treatment.
Q: What if my fish shows no improvement after 5 days?
A: Discontinue use and consult an aquatic veterinarian. Persistent symptoms may require a different antibiotic or a more specific diagnosis.
