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We now prefer using Maracyn as it's the same active ingredient(erythromycin). The price of API Erythromycin keeps going up multiple times a year. Maracyn has remained a better deal.

This is what we use here at the store and at Cory's fish room to treat every fish we come into contact with. For us we've never had problems using it with inverts, scaleless fish, and plants. We've never had our beneficial bacteria die from this medication, but as with all medications take precautions in case your cycle does crash. 

Commonly used to treat:

  • Cyanobacteria
  • Fin Rot & Tail Rot
  • Columnaris 
  • Open Wounds

Dosing Instructions:

For best results remove activate carbon. For each 10 gallons of water empty on packet directly into aquarium (For 850gm jar, add one scoop [1tsp] per 20 gallons), repeat dose after 24 hours then change 25% of the aquarium water. Repeat treatment a second time for a total of 4 doses, then make a 25% water change. Treatment may be repeated if necessary. Four doses required for full course treatment. 

Treats 100 Gallons. 10 Packets, each treating 10 gallons. 850gm container treats 3270 gallons.

 

 

API E.M. Erythromycin

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We now prefer using Maracyn as it's the same active ingredient(erythromycin). The price of API Erythromycin keeps going up multiple times a year. Maracyn has remained a better deal.

This is what we use here at the store and at Cory's fish room to treat every fish we come into contact with. For us we've never had problems using it with inverts, scaleless fish, and plants. We've never had our beneficial bacteria die from this medication, but as with all medications take precautions in case your cycle does crash. 

Commonly used to treat:

  • Cyanobacteria
  • Fin Rot & Tail Rot
  • Columnaris 
  • Open Wounds

Dosing Instructions:

For best results remove activate carbon. For each 10 gallons of water empty on packet directly into aquarium (For 850gm jar, add one scoop [1tsp] per 20 gallons), repeat dose after 24 hours then change 25% of the aquarium water. Repeat treatment a second time for a total of 4 doses, then make a 25% water change. Treatment may be repeated if necessary. Four doses required for full course treatment. 

Treats 100 Gallons. 10 Packets, each treating 10 gallons. 850gm container treats 3270 gallons.

 

 

Customer Reviews

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J
J.
ALWAYS keep this on hand

I have been in the hobby for 40 years and ALWAYS keep this on hand for emergencies. You never know when you will have an issue that will need immediate treatment. Like Cory says use it with General Cure too. A little rant-My father is a pharmacist and for the way it is sold he said it is way over priced (Not Corys fault!). If you could get a prescription you could get it for $0.25 for a 250mg tablet. It is a super cheap drug that has been around for decades. Well, we have to pay this price without a prescription. The down side is that it will kill off the good bacteria too.

B
B.
Amazing Service

I'm fortunate in that I live reasonably close to Co-Op. When I placed my order, a store member who knew me called me and asked if I wanted it shipped, or if I'd like it held for the next time I came in. To me, this level of service is basically impossible to find in nearly any retail field - and it's the reason I've made Co-Op my LFS even though it's not the closest - it's worth the service.

The EM is wonderful, I've adopted Cory's quarantine regime and it's been wonderful for my little fishy friend's health. I love the larger size as it's much easier to dose larger tanks if needed and the value for a larger jug is awesome - it'll last me a long time, which makes the value even better. Thanks Cory and the Co-Op team, you folks are stellar from your advice, to products, to service - everything is 5 star about you.

P
P.J.
Good to have on hand

I try to keep it on hand to make sure I can address any issue should it arise. I try not to use it if possible as it throws the balance of the aquarium off, but sometimes you just have to treat the fish and deal with it.

D
D.H.
Skin Infections

Worked really well for skin infections on my cardinal tetras

H
H.L.
Fin Rot

Works really well. I readily keep this med on hand. Have seen great success in treating fin rot with this.