FDA approves eugenol sedative for wild fish
The FDA has approved AQUI-S E10%, an eugenol immersion solution, for sedating wild freshwater finfish during field management activities.
The US Food and Drug Administration approved a new sedation option for wild freshwater finfish on August 25, 2026. The product, called AQUI-S E10% (eugenol immersion solution), is designed for field use by fisheries professionals to sedate fish to a handleable condition for management tasks.
This immersion solution is specifically for managing wild fish populations as a resource. It is not approved for use in aquaculture or hatchery settings. Professionals use sedation to handle fish for procedures like spawning, tagging, weighing, measuring, and collecting biological samples.
Fish are sedated via a static immersion bath. They are placed individually or in small groups into a container of water treated with the product and removed once sedated. After recovery, they can be released directly back into their environment.
Effectiveness across species
The US Fish and Wildlife Service tested the drug's effectiveness on numerous freshwater species. The list includes rainbow trout, brown trout, cutthroat trout, lake trout, walleye, yellow perch, Nile tilapia, blue catfish, hybrid striped bass, channel catfish, common carp, and fathead minnows.
Studies monitored time to sedation, recovery time, behavior, and 24-hour survival. According to the FDA, all fish survived the monitoring period with no adverse reactions noted. Some fish exhibited transient behaviors like headshaking or coughing upon initial exposure, but these resolved within seconds.
Sedation and recovery times varied by fish type and dosage.
| Fish Group | Dosage (mg eugenol/L) | Average Sedation Time (minutes) | Average Recovery Time (minutes) |
|---|---|---|---|
| Salmonids (e.g., trout) | 25 | 1.3 to 3.2 | 3.6 to 10.8 |
| Non-salmonids (e.g., catfish, perch) | 40 to 72 | 0.9 to 3.1 | 1.9 to 14.4 |
Safety and user precautions
Safety studies established an adequate margin of safety for the product. Tests on fingerling rainbow trout, yellow perch, and channel catfish at target and higher concentrations found no gross lesions or significant treatment-related tissue changes. The most common observation was brief headshaking in trout and perch during the first 15 to 30 seconds of exposure.
The FDA has set a 0-day withdrawal period for field use, meaning fish can be released immediately after recovery. The agency determined that eugenol residues in edible tissue remain below levels considered safe for human consumers, posing no public health concern. Consequently, no tolerance level was assigned.
The product label carries important warnings for handlers. AQUI-S E10% is harmful if swallowed and can cause allergic skin reactions. The FDA advises anyone handling the solution to wear protective gloves, a lab coat, and eye protection. Users must avoid skin and eye contact, avoid ingestion, and wash hands thoroughly after use.
With this approval, the FDA has updated its related guidance document. Guidance for Industry #150, which previously warned that clove oil and its components like eugenol were not approved for fish, now lists AQUI-S E10% as an approved sedative for freshwater finfish. The product, sponsored by AQUI-S New Zealand Limited, will be available over the counter.
