Rust spot/burn spot disease

"Burn spot" or "rust spot disease" are umbrella terms for problems involving a melanisation (black/brown discoloration) of the exoskeleton. This could be due to small injuries, local bacterial, fungal or other infections. So the diagnosis is based on brown discolorations, not on a specific pathogen.

Rust or burn spot disease thus might have different reasons, however, these cases all have the one thing in common: if the discolored spots are gone after a molt, the problem for the specific animal is gone, too.

However, if you have several shrimp with brownish discolorations or even necroses (dying tissue) you should start searching for reasons. This will primarily have to consist of overthinking the living conditions in the tank (stocking density, bacterial count, biological stability of the aquarium), which makes a lot more sense than searching for pathogens with expensive and time-consuming lab tests.

Experiences from commercial (food) shrimp farming show that in these cases practically always a number of different pathogens are present. Bettering the living conditions in the breeding tank/pond always does the trick here, too, though.

by Werner Klotz

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