Shrimp-safe medications and copper

The short answer

Shrimp are invertebrates, so they react to chemicals very differently from fish. Something that is harmless or even helpful for a fish can wipe out a colony, and the damage is often done before anything looks wrong.

Why copper is the big one

Copper is toxic to shrimp and other invertebrates at very small amounts. It is also an ingredient in some fish medications and algae treatments, so it is easy to add by accident. Because the harm builds up quickly, losses can be sudden. If your shrimp are dying and you recently added anything to the tank, see why shrimp die and stop adding products while you work through it.

Where copper and other risks come from

Check labels for these before anything goes in the tank:

• Fish medications and algae treatments. Look for copper or copper sulfate in the ingredients, and be cautious with any product that does not say it is invertebrate safe.
• Fertilizers and plant products. Some contain trace copper. Choose ones that say they are shrimp safe, and see live plants for shrimp.
• New plants. Plants from stores can carry pesticide residue, so rinse them well and consider a short quarantine before they go in.
• Household sprays and fumes. Air fresheners, cleaners, aerosols and pest or flea products used near the tank can reach the water. Wash and rinse your hands well before working in the tank.
• Plumbing. Water that has sat in copper pipes can pick up copper, so let the tap run for a moment before filling buckets.

Treating sick fish safely

If you keep fish with shrimp, set up a small hospital tank with a heater and a gentle filter, and treat the fish there. Do not dose the main tank, since medication is hard to remove and the filter bacteria can be affected too. See shrimp tank mates for which fish are good company. Rinse any net or tool used with medication before it touches the shrimp tank.

If shrimp were exposed

Stay calm and avoid adding anything else. Move the shrimp to clean, dechlorinated water that matches their usual parameters if you can, or do a gentle water change, and use fresh activated carbon in the filter. Carbon removes many medications but not all of them, so also read the product maker’s guidance. Copper test kits are sold for aquariums and can help confirm a suspicion. If you are not sure, bring a water sample to the Convoy store and we will help.

A sick shrimp is usually not an infection

Most shrimp problems come from water quality, a bad molt or a sudden change rather than from a disease that medication can fix. Check the basics first: water parameters, chloramine treatment and temperature. Adding a treatment to a tank that did not need one is a common way to turn a small problem into a big one.

Questions we get asked

Is copper really that harmful to shrimp?

Yes. Copper is toxic to shrimp and other invertebrates at very low levels, even though many fish tolerate it. Treat any product containing copper as unsafe for a shrimp tank.

Can I use fish medication in a tank with shrimp?

Assume not. Unless the label clearly says it is safe for invertebrates, move the sick fish to a separate hospital tank and treat them there.

Where does copper come from?

Common sources are copper-based fish medications and algae treatments, some fertilizers and plant products, and water that has sat in copper plumbing. Always read the ingredient list.

What should I do if I think shrimp were exposed?

Do not add anything else. Move the shrimp to clean, dechlorinated water that matches their usual parameters if you can, or do a gentle water change, and run fresh activated carbon in the filter. Carbon helps with many products but not every one, so check the product label for advice.

How do I treat algae without harming shrimp?

Start with the causes: less light, fewer nutrients, more plants and manual removal. Only use a product that is clearly labeled safe for shrimp, and add it cautiously.

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