Will copper from fertilizers hurt my shrimp or fish?
January 10, 20201 min read
Shrimps and fertilizers
Shrimps are sensitive organisms generally, with CRS strains and higher grade shrimp being more sensitive than RCS & neocaridinas. Neocaridinas are generally hardier as well, and are a great choice for planted tanks.
Shrimps are sensitive to water quality and other stress factors (like predatory fish). Because of their delicate nature, many aquarists will end up killing them in their tanks - a number of folks will be dosing fertilizer at the same time and this results in wrong causation.
Most commercial fertilizer do not have enough Copper (or any other harmful chemical) in them to affect livestock. I have also tested various commercial fertilizers on my cull shrimps in controlled overdose tests. Besides algicides (that come with shrimp warning labels) and Seachem Excel (not a fertilizer), every commercial fertilizer I tested failed to kill shrimps at 5-10X overdose rates. So shrimps are easy to kill, but not with fertilizer.
I keep neocaridina shrimp in all of my planted tanks, and they breed like flies despite rich fertilization and CO2 levels.
When is copper a concern?
Some tap water sources have high copper levels (due to copper pipes usually). If your tap has high copper levels, RO is the only solution if you want to keep shrimps. Many commercial algicides may contain copper as well. Over zealous DIY fertilizer users may also hit lethal levels of copper, but it takes quite a bit of overdosing.