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API E.M. Erythromycin Fish Medication

$17.95 - $219.98
(2 reviews) Write a Review

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API® E.M. ERYTHROMYCIN powder helps broad spectrum treatment and control of bacterial disease, such as body slime, mouth fungus, Furunculosis (open lesions and swelling), bacterial gill disease, fin and tail rot, open red sores, mouth fungus and hemorrhagic septicemia (blood spots without sign of skin damage). For use in both freshwater and saltwater aquariums. Can be used with any API Ich, fungus or parasite remedy to help prevent secondary bacterial infection. This medication will not color the aquarium water.  

It can be used in combination with API General Cure Fish Medication to quarantine new fish.


For each 10 gallons of water, empty one packet directly into aquarium. Repeat dose after 24 hours. Wait another 24 hours then change 25% of the aquarium water. Repeat this treatment for a second time, for a total of 4 doses. Then make a final 25% water change and add fresh activated carbon or replace filter cartridge. 850 g jar comes with a measuring spoon.


  • 10 packets/30 oz, or
  • 850 gram jar (bulk)


FIN & TAIL ROT: Fins appear ragged and split. In severe cases, fins and tail are almost completely eroded. Secondary fungal infections, observed as white, "cottony" growth, commonly occur.

OPEN RED SORES: A bacterial infection that causes open red sores on body. Infection can range from very small ulcers to deep skin lesions. Coloring can range from reddish or gray ulcers to very dark areas associated with necrotic (dying) tissue.

MOUTH FUNGUS: Common bacterial infection that affects the mouth and other soft tissue. Fungus-like in appearance with red periphery. If left untreated, severe erosion and lesions will develop.

HEMORRHAGIC SEPTICEMIA: A bacterial infection of the bloodstream. Fish may show blood streaks on the body and fins, bleeding (red patches) and localized swelling.

BACTERIAL GILL DISEASE: Fish may breathe heavily and show bright red gills. Fish may sit at bottom of aquarium or near the water's surface. However, visual diagnosis is often difficult. 

Reviews (2)

  • 5
    Posted by Norma on 15 Mar 2022

    Best product

  • 4
    API E. M. Erythromycin
    Posted by Mike Stroup on 25 Nov 2021

    It did what I needed for my new fish.