When a fish is ill and it’s apparent that the illness is bacterial in nature we often refer to it as Aeromonas. We accuse this bad bacteria for a host of illnesses that other types of bacteria create. There’s actually several possible culprits including Pseudomonas, Flexibacter, Streptococcus and Edwardsiella. Aeromonas is by far the most commonly seen and causes dreaded holes in the skin. What they all have in common is that they all are deadly. Wage war on these bad bacterias before they wage war on your fish!