Copper and algae treatments: what is deadly for Cherry shrimp
The Cherry shrimp (Neocaridina davidi) is a hardy invertebrate in many respects, but it has one clear weak point: copper. Find our other health tips in the fish care section.
Why copper is so dangerous for crustaceans
Freshwater crustaceans, which include dwarf shrimp, are markedly more sensitive to copper than fish: research on atyid shrimp closely related to the Cherry shrimp shows marked copper toxicity, with effects on behaviour and survival at concentrations widely tolerated by fish (research on Google Scholar). Water that would cause no problem for a guppy can therefore wipe out a shrimp colony.
Where copper comes from in a tank
Three main sources: some algae and parasite treatments sold without distinction for any aquarium, tap water that has sat overnight in old copper pipes, and liquid plant fertilisers or supplements dosed incorrectly. Always check the ingredient list before using a product in a shrimp tank, and favour freshly drawn tap water over water that sat in the pipes overnight.
Prevention rather than cure
In a shrimp nano tank, test water quality before any addition and avoid any product not explicitly labelled "invertebrate safe". The basic equipment recommended for this type of tank is covered in our nano shrimp tank: essential equipment guide. If in doubt about a treatment, isolate the shrimp in a hospital tank first, just as you would for sick fish.
Frequently asked questions
My shrimp died suddenly after an algae treatment, why?
This is the classic sign of copper poisoning: stop the product immediately and perform a partial water change.
Does an activated carbon filter remove copper?
It absorbs some of it but does not guarantee complete removal: prevention at the source remains the best protection.
Are fish in the same tank also at risk?
Concentrations dangerous to shrimp are generally well tolerated by most fish, which is exactly what makes the problem easy to miss.
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.