- Treats bacterial infections
- Safe for aquarium plants
- Safe for shrimp, snails, and other invertebrates
Fritz Maracyn® is a specially compounded broad-spectrum antibiotic (erythromycin) which has been shown to be effective against a number of pathogenic bacteria associated with ornamental fish disease. It was developed for complete but gradual dissolution in water. It is primarily effective against gram-positive pathogenic organisms. 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 infection.
For the 10-count and 20-count boxes of Maracyn, the medication comes in individual packets where each packet treats 10 gallons of water. The 100-gram bulk container treats a total of 1,000 gallons of water while the 400-gram bulk container treats 4,700 gallons of water, and both containers come with a scoop for easy dosing. When treating with Maracyn, we recommend using an air stone in the aquarium, which may temporarily cause excessive foaming at the water surface.
Customer Reviews
Literally the best company for your freshwater aquarium.
One of my Julii's had a white cottony spot near the end of his tail. I chose to treat the whole 10 gallon aquarium since there are only six corydoras in it. I added 3TBS of aquarium salt and when there was no improvement at all I decided to change tactics. Per Cory's video instructions I added 1 tsp Ick-X and 1 packet of Maracyn. This was 3days ago. The water is hazy, but the fungal spot is gone. I am going to continue to "let it sit" as the video instructed for the full seven day course. I bought the trio of meds when I got the fish and was grateful to have them on hand when the need arose. Aquarium Co op, thanks for taking the guess work out of treating sick fish!
Well, either Fritz started diluting their Maracyn or decided that that it needed to be given at a higher dose than in the past. Here are some facts. The last bottle I purchased right here on Aquarium Co-Op says right on the front label Net Wt. 60 grams and right next to that it says Treats 1,000 Gallons and on the back label it says “Add one level scoop (approx. .6 gram) per 10 gallons of water.” A little math says 60/.6 = 100 scoops x 10 gal. = 1,000 gallons, the older smaller scoop per D.B.I.'s observation. All the math works. Now let’s jump to the new size of 100 grams: Net Wt. 100 grams, Treats 1,000 Gallons (what, use more for the same gallons??), so now it takes an entire gram to treat 10 gallons of water where it use to only take .6 grams, thats a 67% increase in use of medicine. Then look at the 400 gram container: according to the Co-Op web site Net Wt. 400 grams, Treats 4,700 Gallons, which if the Co-Op site is correct then this would be a ratio of approximately .85 grams/10 gallons which starts to make sense with what D.B.I. noted with the scoop being 1.7 cc except that the scoop would be good for 20 gallons not 10 gallons (.85x2=1.7). (It should be noted here that Fritz says that 1cc approximately equals 1 gram of the powder.) but to go from .6 grams for 10 gallons to 1.7 grams for 10 gallons would be a 283% increase. Something is way off here. It needs to be noted that other sites selling the 400 gram bottle, they say that the 400 grams treats 4,000 gallons which is the same ratio as the new 100 gram bottle. Also, on the D.B.I, post he shows the back of the bottle label and assuming that is the 100g bottle it says that Each Dose Contains 200 mg Erythromycin Activity which is the same as it says on my older 60 gram bottle, so did Fritz change the dilution of the powder so that the new larger scoop still contains the same amount of active ingredient or is there a mistake in the scoop they now include or are the instruction incorrect? Lots of questions, what I do know is that the .6 grams to 10 gallons of the older bottle works just fine. So, it appears that both the Co-Op and the Fritz company have some explaining and likely corrections made to the website(s). Photos of the 60 gram bottle which only expired 04/18/2024, so not that old of a bottle. Do your homework as the jury is currently out on this product as to the correct dosage. The low rating is not for the product itself or to the Co-Op, but for the lack of correct instructions.
I had issues with UPS in the shipping for this product, and Candi and Sarina responded within ten minutes to help fix the issue! Fast service and great product!
I medicated my tank according to directions and my fish seem better. Thank you so much for the quick turn time!
Works as stated for Finn rot
It’s helped me save fish time and time again love that you can get it in a small amount or a breeder size
Fritz Maracyn
Item name quickly. Needed meds ASAP for sick fish
This product gets the job done. I really appreciate that the co op sells products they use. The support system is extremely valuable