As pet owners, we always want the best for our pets. Unfortunately, disease or injury happen in life and there are certain times when the peaceful end of a life may be better than the pain of treatment or the suffering caused by the continuation of that life. Since our pets can’t talk, the decision to humanely end a life is left up to us as pet owners. We do not take this decision lightly.
All that being said, there are certain times when humane euthanization of our pet shrimp may be required, like if they are half eaten, experience severe muscular necrosis, or have a late-stage Cladogonium infection. In these cases, the method we recommend - and the one commonly used by scientists - is to use clove oil to anesthetize, followed by freezing. This offers a pain-free way to end your shrimp’s life. Let’s go over a little bit of the science.
We are basing our instructions off this paper published in 2018, which tested the effect of eugenol (the main component of clove oil) on Palaemonetes sinensis (Grass/ghost shrimp), a shrimp of similar size to Neocaridina and Caridina. In it, the researchers found 100-300 mg/L of eugenol led to Anesthesia Stage 2 within 20-40 minutes at temperatures above 16°C (60°F). For reference, Anesthesia Stage 2 is defined by a loss of consciousness and no reaction to stimuli such as movement or light.
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How quick and effective eugenol is depends on the shrimp size, temperature, and other water quality measurements. Since we won’t have all these numbers in a real-life situation, our goal is to ensure sufficient anesthetization in a reasonable amount of time. Because of that, we recommend dosing 300-500 mg/L of eugenol (don’t worry, we’ll explain how to estimate the dosage later), which was shown to reach Anesthesia Stage 2 within 5-10 minutes over a wide temperature range and regardless of shrimp size.
Most clove oil does not say the concentration of eugenol in it but, according to Wikipedia, clove oil is approximately 60-90% eugenol. Since our goal is to ensure anesthetization, we will assume it is the lowest concentration, which will give us the highest calculated dosage. The weight of clove oil is 1 g/mL, so it takes 0.5g of clove oil in a liter to get 300 mg/L, or approximately 0.8 g of clove oil for 500 mg/L.
If you only have a dropper for clove oil, each drop is approximately 0.05 g, so you would need between 10-16 drops of clove oil per liter to anesthetize your shrimp within 5-10 minutes.
We hope this article helps you understand the science behind the euthanization methods we use and explains our thought process behind our dosage recommendations. It’s never a fun process but we can at least ensure that it’s painless for the shrimp.
We’re sorry for your loss. Feel free to reach out to us for support at contact@shrimplyexplained.com.
Sincerely,
Rick and Shrimply
Citation
Li, Y., She, Q., Han, Z. et al. Anaesthetic Effects of Eugenol on Grass Shrimp (Palaemonetes sinensis) of Different Sizes at Different Concentrations and Temperatures. Sci Rep 8, 11007 (2018). https://doi.org/10.1038/s41598-018-28975-w