Ich infection in fish causes which skin lesion?

Ich infection in fish causes which skin lesion?

• A. Red ulcers on skin
• B. White plaques on skin/scales
• C. Fuzzy growth on gills
• D. Black spots on scales

Answer: (B)

Ich infection presents as white plaques on the fish’s skin and scales. The parasite attaches to the epidermis and forms tiny, cyst-like spots that appear as small white colonies, giving the classic “white spot disease” appearance on body and gills. This sign is the hallmark that differentiates it from red ulcers (usually bacterial), fuzzy growth on the gills (often fungal like Saprolegnia), or black spots (a different pigment/parasite issue). Recognizing these white plaques helps in diagnosing ich and guiding treatment that targets the parasite through all life stages and appropriate water conditions.

Ich infection presents as white plaques on the fish’s skin and scales. The parasite attaches to the epidermis and forms tiny, cyst-like spots that appear as small white colonies, giving the classic “white spot disease” appearance on body and gills. This sign is the hallmark that differentiates it from red ulcers (usually bacterial), fuzzy growth on the gills (often fungal like Saprolegnia), or black spots (a different pigment/parasite issue). Recognizing these white plaques helps in diagnosing ich and guiding treatment that targets the parasite through all life stages and appropriate water conditions.