A 50 gram jar of Erythromycin is the equivalent of 200 packets commonly available in the fish hobby.  Save by purchasing in bulk!
Erythromycin is a common antibiotic used to treat a variety of bacterial ailments. Non-toxic to invertebrates.
Common behavioral changes that indicate a bacterial infection include clamped fins, swollen eyes, gills held open, pumping gills and gulping through mouth, patchy coloration, change in swimming behavior, becoming shy or hiding, etc.
Treatment Against: Columnaris, Fin and Tail Rot, Popeye and other diseased caused by Flavobacterium columnare, Haemophilus piscium, Aeromonas punctata, Aeromonas hydrophila, and Cytophaga aquatilis bacteria. Used in freshwater or saltwater.
Can also be used in low dose to help combat cyanobacteria when all other attempts have failed (hydrogen peroxide, spot treating with Seachem Excel or other glutaraldehyde, and increased maintenance to minimize nitrogen waste in the tank which the bacteria feeds off of).
Dosage: 250-500 mg (1/4 teaspoon) per 20 gallons every 24-hours with a 25% water change prior to dosing. Repeat 10-14 days. Can be stopped after 5 days if no improvement.