HCA: Hermit Crab Association

Is their any scientific evidence that copper sulphate and eq kill? I mean I don't doubt that they do, but if we ever expect to get those bad foods off the market we are going to need some hard evidence to back up our claims.

Copper is a known invertebrate killer. You can put copper strips in your garden to kill snails. But I don't know if there's any studies showing that the amount of copper sulphate in hermit crab food is harmful to the crabs.

I don't know if there are any studies showing what ethoxyquin does to invertebrates. It is illegal to use in human food; I think it was linked to cancer. It's rarely used in cat and dog food, because a lot of breeders were losing litters and complaining about unhealthy animals when the food did have ethoxyquin in it. But even so, the cat and dog food manufacturers only stopped using it because of complaints, because people weren't buying their brand, not because the government made them stop using it for safety reasons.

As far as I know, the evidence of the harm to hermies from those ingredients is entirely anecdotal. But there is pretty good evidence that fresh foods are so much healthier for your hermies (or you, or your other pets).

I've searched the scientific literature for copper toxicity in decapods and the nearest data I can find are for Penaeus monodon - the Tiger Shrimp. The LC50 (concentration required to kill half of the animals it was tested on) for copper sulfate in P. monodon is 1mg/L for shrimp weighing 6.25g. I we were to scale this up to a crab weighing about 60g, that's 10mg/L as the LC50 [this is a legitimate calculation - we scale up rat LC50s and LD50s to humans in exactly this way]. 10mg = 0.01g per litre, which is quite a lot. How much is present in these crab foods?

They do note that copper sulfate seemed to suppress appetite in shrimp too.

Reference:
Chen JC, Lin GH (2001) Toxicity of copper sulfate for survival, growth, molting and feeding of juveniles of the tiger shrimp, Penaeus monodon. Aquacult. 192(1): 55-65.

Well, quite a few people have crabs that have had severe molting problems, thought to be linked to it.

I am not totally sure this was due to ethoxquin, but I did have some very bad molts when I used commercial foods. During soem molts, I had crabs lose limbs, ad I know it wasnt because there was an attacker crab. I have also had one crab that was so severley deformed he only had one eye and one claw. I have also had crabs come up with spots of bad exo when I fed commercial foods. PLease note that all of these crabs died except the one with missing limbs (not deformed)This is not scientific, however this does prove that it can be dangerous to crabs.

Copper sulfate is an insecticide, and is listed for accumulation and mortality in crustaceans, though it is only slightly toxic, meaning it would take a lot to cause problems:
http://www.pesticideinfo.org/Detail_Che ... cotoxicity

It looks like 25 to 200ppm (25mg per kg) is harmful over extended periods. CS is limited to 1ppm in drinking water.
http://pmep.cce.cornell.edu/profiles/ex ... e-ext.html

Ethoxyquin isn't listed as anything harmful (except fungicide). But there's been a lot of anecdotal evidence of it's harm to pets due to long-term exposure.

I think the only proven effect is that it elevates levels of Protoporphyrin IX in the liver.
http://en.wikipedia.org/wiki/Ethoxyquin


EQ just becomes the posterchild of the artificial vs. natural war.

I do wonder if the issues caused by commercial foods were anything to do with malnutrition or deficiencies?

Idk so im guessing no one really knew if it was the problem they just assumed that it was bad in some cases and decided to stop it all together?

hermiefanatic wrote:I am not totally sure this was due to ethoxquin, but I did have some very bad molts when I used commercial foods. During soem molts, I had crabs lose limbs, ad I know it wasnt because there was an attacker crab. I have also had one crab that was so severley deformed he only had one eye and one claw. I have also had crabs come up with spots of bad exo when I fed commercial foods. PLease note that all of these crabs died except the one with missing limbs (not deformed)This is not scientific, however this does prove that it can be dangerous to crabs.

I agree w/ this completely...I had many bad molts when I fed my crabs commercial food w/ those ingredients. I had some come up w/ missing limbs, or holes in their new exo. It stopped happening when I STOPPED giving them the "Hermit Crab Variety Bites"

Even though they really would run for the bowl when I put it in there, I am sure it was the main cause of their problems...I have had no more issues since I started giving them natural foods....