While researching the effects of Ethoxyquin on pet freshwater invertebrates, I found a 2005 reassessment of inert ingredient tolerance of ethoxyquin, commissioned by the US Environmental Protection Agency (EPA). The reassessment states that "studies indicate that ethoxyquin is toxic to aquatic invertebrates, and mildly toxic to fish" when ingested. To my knowledge, the studies cited are the only ones conducted on fish and invertebrates.
The rumor that all fish foods contain ethoxyquin because all fishmeal contains it, is probably what fueled the latest backlash by consumers of dog and cat food. It was further fueled by the suggestion that ethoxyquin could be hidden from the label list of ingredients if it was used to preserve an ingredient in the fish food. This rumor was perpetuated by a fish food manufacturer who was attempting to justify the inclusion of ethoxyquin in their product, and consequently made these statements online.
There are, of course, sources of ethoxyquin-free fishmeal and more are popping up all the time due to the increase in demand for 'natural' products. The rumor stating that all fishmeal MUST contain ethoxyquin would only apply to fishmeal being transported by boat and even then, a special exemption may be obtained. The second rumor stemming from this misleading information regarding labeling is entirely false - ethoxyquin content specifically must be stated on the label, whether it was added intentionally or inadvertently through an ingredient.
This is a classic case of inaccurate information found online by consumers and the damage it can cause to the pet food industry, especially when the source seems reputable.
This brings us to the three points that I will address in this article:
1. Ethoxyquin should not be used in fish/invertebrate food.2. What should we do when a baseless rumor spreads like wildfire online?3. How can the fish food industry turn this fish poo into a salmon steak?
Ethoxyquin should not be used in fish food
This may be a simple matter of educating the manufacturers of fish food, or perhaps informing them that consumers are aware of these facts and they're going to lose money if they don't remove it from their product. We do not increase the bottom line by using less expensive preservatives, if our preservative of choice results in the loss of sales. That is precisely what many manufacturers of dog and cat food concluded when they decided to no longer use ethoxyquin, even though there were no studies proving that it is toxic to mammals.
It is crucial that this preservative no longer be used in fish/invertebrate food, not only to please consumers as it was with dog and cat food, but because it threatens the health of the very creatures its designed to feed. Invertebrates are commonly found in freshwater aquariums today - both shrimp and snails are wildly popular. Those who only keep fish are not at all comforted by the knowledge that ethoxyquin is 'mildly' toxic to fish.
I was unable to obtain a copy of the studies cited by the EPA, but perhaps someone else will have better access to the proper channels. I did contact Wildlife International as they conducted the study for the EPA, but they are unable to release the studies without the EPA's consent. Following are the studies you will be asking the EPA about:
MRID No. 43978101 (1996) Ethoxyquin Technical A Dietary LC50 Study with the Northern Bobwhite
MRID No. 43978301 (1996) Ethoxyquin A 96-Hour Flow-Through Acute Toxicity Test with the Rainbow Trout
MRID No. 43978401 (1996) A 43-Hour Flow-Through Acute Toxicity Test with the Cladoceran
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