Fish Pen 500mg 30 Count Fish Biotic Antibiotic

Fish Pen 500mg 30 Count Fish Biotic Antibiotic

Fish Pen 500mg 30 Count Fish Biotic Antibiotic

$65.99 $49.99

Fish Pen 500mg 30 Count Antibiotic

Fish Pen® is the most trusted fish Penicillin that fights bacterial diseases in marine and freshwater fish.  


  • Wields a bactericidal action on gram-positive and some gram-negative bacteria
  • Broad-spectrum antibiotic for use in fish
  • Effective against a number of pathogenic bacteria
  • For use in marine and freshwater ornamental fish diseases

Fish pen is a proven leader in the world of fish antibiotics. Use this fish medication to treat a number of diseases and conditions in your marine or freshwater friends, including infected eyes, pop-eye, fin or tail rot, skin ulcerations, columnaris disease, gill disease, and more! Fish Pen 500mg is a broad-spectrum antibiotic that controls gram-positive and some gram-negative bacteria in fish. It works by halting the multiplication of bacteria associated with both freshwater and saltwater ornamental fish diseases. This fish antibiotic is useful for controlling some common bacterial diseases in fish including Dropsy, Fin Rot, Red Pest, and diseases caused by bacteria such as Aeromonas, Pseudomonas, and Mycobacterial (Gill diseases and Chondrococcus). With Fish Pen, there’s no wrangling or sequestering your fish for treatment. Shop My Hooves and Paws today for these and other fish antibiotics and fish supplies to keep your scaled friends healthy and happy!


  • 500mg capsules of penicillin for fish 
  • For marine and freshwater fish


*All Fish Pen products qualify for free standard United States shipping — regardless of the quantity, no matter how much you buy. It will appear in your cart after you enter your information at checkout.

Need assistance with your order? Call us at 760-247-5523 or email us at We’re happy to help you!

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