View Full Version : Maracyn or Erythromycin for Red Slime?

02/02/2007, 02:46 AM
I went to my local Petsmart to find these products but now I dont know which one to buy to treat my Red Slime algae. Which one is better? I was going to get the Maracyn but came to find out that there were 3 different Marcyns on the shelf. If Maracyn is recommended, then which one should I buy that is the most effective?

Ive read previously that Maracyn and Erythromycin comes in capsules but I was only able to find the ones in the powder packages. Are these the same as the capsules? How EXACTLY do I treat my tank?(29 gallons). What are the steps in dosing and does it pose any threat to the health of my corals and anemone? Thanks a millioon for your help.

02/02/2007, 03:13 AM
I think Maracyn contains erythromycin.
Maracyn comes in a freshwater and saltwater package but I could not tell from the label
what the difference was in ingredients other than possibly dosage.

It does a great job of killing your red slime but it will just come back eventually if you don't
get a handle on what is causing it to grow in the first place.
My friends tank crashed and he eventually lost most of his corals after he dosed with Maracyn and his tank was a 29 gallon also. If I recall correctly, he said he dosed 1 tablet of the saltwater Maracyn. If you are going to use it, I'd do a waterchange when you see the slime dying off.

George Gouveia
02/02/2007, 03:17 AM
[after reading abit more about red slime, i removed my remark about not understanding why using maracyn]

Product Description:

"Maracyn is a specially compounded broad-spectrum antibiotic which has been shown to be effective against a number of pathogenic bacteria associated with ornamental fish disease. Symptoms of clamped fins, swollen eyes, heavy or rapid breathing, patchy coloration, change in swimming behavior or corner hiding can be signs of possible bacterial infections.

Use Maracyn to treat the following: Body fungus, (white grayish material covering most of the body), Fin and Tail Rot (split, ragged and deteriorating fin and/or tail), Popeye (protruding eyes, may be cloudy or hazy), Gill Disease (swollen, discolored gills, gasping for air and a decrease in activity), and secondary infections"

You can check this link to see if it contains information on how to treat the cyno, i don't really think that maracyn is indicated for that.


02/02/2007, 06:27 AM
Typically any chemicals that kill the algae will allow the phosphates and nitrates to be absorbed back into the water causing a repeat outbreak of the algae in about a week. You need to improve your water quality! I would siphon off as much of the algae as you can and do a water change. Are you using RO/DI water for your water source? If not you may be facing an uphill battle.

02/02/2007, 07:21 AM
You shouldn't need to resort to chemicals to beat cyano. I speak from firsthand experience, having recently battled it myself in my 250. In my case, I think I helped it gain a foothold by overfeeding. Start by syphoning and/or blasting it with a powerhead to break it up, and remove everything you can. Skim heavily and reduce feeding. As the nutrient levels fall, growth will slow and you will win. I have a few traces of it left in my tank, but nothing like it was a few weeks ago. In another few weeks I think it will be gone completely.