What is Saprolegnia?

• A. A bacterium that infects rodents
• B. A water mold commonly found in aquaria
• C. A virus that causes foot rot in ruminants
• D. A parasite that causes skin lesions in amphibians

Answer: (B)

Saprolegnia is a water mold (an oomycete) that lives in freshwater environments and is commonly found in aquaria. It appears as cottony, filamentous growth on fish skin or eggs and tends to act as an opportunistic pathogen when water quality is poor or fish are stressed. It is not a bacterium, not a virus, and it is not a parasite of amphibians. This makes the description of a water mold commonly found in aquaria the best fit. In lab settings, preventing Saprolegnia involves maintaining clean, well-filtered water, avoiding overcrowding, quarantining new stock, and promptly removing infected material.