I have some Wardley Shrimp Pellets and I see copper sulfate in the ingredients...won't this harm my inverts? (Blue lobster, fiddler crabs, dwarf shrimp)
I wouldn't know because I avoid feeding my inverts anything with copper, but only because I heard it was bad, not that I have any experience at it.
i've never seen ill effects in my ghost shrimp, but i stopped feeding this stuff to them a while ago. if i need a sinking pellet, i think hikari's algae pellets are copper-free (but definitely check before you buy). alternatively, just soak some food in water beforehand.
It is only a trace amount but I would avoid any copper with inverts. It does not take much to kill snails for example. Invertebrates, like other living things, do need a trace of copper in their food. Some of them even use copper instead of iron in their blood, which makes it blue or even green instead of red. It is common to simplify and say all invertebrates have copper based blood. The naturally present copper in foods is the safe way to obtain what is needed. Using a food with copper supplemented is unnecessary. Copper supplements, like copper containing medications, can precipitate in the aquarium and build up. Then with some shift in water parameters such as pH, temperature, or hardness, all of the stored up copper goes back into solution. There would be no problems with the copper additive until there was something else handy to blame it on. You would have just done a partial water change and automatically guess that the water company put some toxic chemical treatment in the water supply. If you want to see what a little copper sulfate can do, look at the pictures in this link below. It can change the color of hardened concrete.
The short answer would be that they're safe for your invertebrates. I've been feeding mine food with copper sulfate for years. The long answer would that copper sulfate is a compound, which isn't as dangerous as elemental copper - the type that could be found in tap water, or leaching from pipes, etc. The trace amounts found in fish food also isn't nearly enough to harm them, and may even be beneficial. Copper, while lethal when there's too much, is actually essential for invertebrates in smaller amounts. They need copper because it is used to carry oxygen in their blood and deliver it throughout their body - some brands of food that's made specifically for invertebrates (notably Hikari's Shrimp Cuisine) even make note that copper is included for this reason. Another thing to keep in mind is that many fish food, even those without copper sulfate in their ingredient list, actually do contain copper within their other ingredients - such as fish meal, seaweed, etc. If food with copper really was dangerous, then we'd have a really small amount of food choices to feed our inverts.
