Petshrimp.com Discussion Forum

Has there been any serious study on the toxic levels needed to be harmful to shrimp, snails and crayfish? Copper and other heavy metals have long been the boogeyman of inverts in the hobby.

The reason I ask is that I've been feeding rabbit pellets to by inverts for some time. The ingredients list copper sulphate (way down on the list). Most turtle foods also list it. The wild snails I keep with my turtles show no ill effect. The shrimp and crayfish are breeding like crazy.

There must be some threshold for toxicity, or maybe the form of copper in copper sulphate isn't as toxic as some others?

There must be some threshold for toxicity, or maybe the form of copper in copper sulphate isn't as toxic as some others?

Interesting, we won't know for sure unless there are/have been trials or experiments done. Does anyone out there have any experiences or data to share?

not too shure but maby the reason its safe is because its a copper compound and not just pure copper dissolved in the water? if that is correct then id be carefull because if there was another element that could displace the copper in the copper sulphate for example iron"In an illustration of a "single metal replacement reaction," iron is submerged in a solution of copper sulfate. Upon standing, iron dissolves and copper precipitates.
Fe + CuSO4 → FeSO4 + Cu"
then that would be bad.
some other things i found out about it
"A dilute solution of copper sulfate is used to treat aquarium fish of various parasitic infections, and is also used to remove snails from aquariums. However, as the copper ions are also highly toxic to the fish, care must be taken with the dosage. Most species of algae can be controlled with very low concentrations of copper sulfate. Copper sulfate inhibits growth of bacteria such as E. coli."
"Effects on aquatic organisms: Copper sulfate is highly toxic to fish. Even at recommended rates of application, 198 this material may be poisonous to trout and other fish, especially in soft or acid waters. Its toxicity to fish 199 generally decreases as water hardness increases. Fish eggs are more resistant than young fish fry to the toxic 200 effects of copper sulfate. Copper sulfate is toxic to aquatic invertebrates, such as crab, shrimp, and oysters. The 201 96-hour LC50 of copper sulfate to pond snails is 0.39 mg/L at 20 C. Higher concentrations of the material 202 caused some behavioral changes, such as secretion of mucous, and discharge of eggs and embryos."

"Abstract
The aim of this study was to determine the acute and chronic toxicity of copper sulfate for juveniles of Penaeus monodon. The 96-h LC50s (median lethal concentrations) of copper on juvenile P. monodon (0.63±0.13 g) were 3.13 and 7.73 mg/l in seawater of 15‰ and 25‰, respectively. The mortality rates of P. monodon juveniles (0.19±0.02 g) following exposure to 0 (control), 0.45, 0.90, 1.80 and 4.50 mg/l copper after 30 days was 0%, 0%, 5.6%, 22.2% and 55.6%, respectively. After 30 days of exposure, the body weight and total length of shrimps exposed to copper at 0.90 mg/l and higher was significantly lower (P<0.05) than those in the control. The 30-day EC50 (concentration that reduced weight gain by 50% of that of the controls) and 60-day EC50 were 2.82 and 1.89 mg/l copper, respectively. The ratio of carapace length to total length of shrimps exposed to copper at 0.90 mg/l was significantly higher (P<0.05) than the controls. Following exposure to copper as low as 0.90 mg/l, P. monodon shortened the time to the first molt, and decreased its growth and molting frequency. Following exposure to copper as low as 5.0 mg/l, P. monodon juveniles (6.25±0.09 g) decreased their feeding. The MATC (maximum acceptable toxicant concentration) was 0.45 mg/l copper based on the growth and molting of shrimps weighing 0.18–1.03 g, and was 1.0 mg/l copper based on the feeding of shrimps weighing 6.25 g.
"

I have a feeling the copper levels in these foods must be very low. One tank I raise blackworms in gets fed the rabbit pellets. The water is chronically green due to green water and the pond snails thrive.

I'll get a copper kit and see what the levels are.

due to the fact that copper salts are hazardous to aquatic life and i not too healthy for humans i doubt that the food will have much copper salt it will probable be a trace element in the food so shouldnt do to much tho what i was going on about would only be if you poured copper sulphate in a your tank but no one would do that