can have difficulty differentiating one stage from another therefore, the correct dose is
particularly important to avoid overdose. For rapid and noninvasive procedures, light anesthesia can be sufficient (e.g.,weighing handing inspection gill scrape, external tagging). However, for invasive procedures and those of longer duration, surgical anesthesia is advised and may need to be accompanied by artificial ventilation of gills by flushing fresh or anesthetic-dosed water with a mouthpiece and pump when necessary. It is particularly important that the water is aerated and maintained at a similar temperature as its normal environment to avoid unnecessary stress to these poikilotherms. Hypoxia can elicit a stress response in fish, which may impede recovery after anesthesia A hypoxic state can also occur if the gills are not fully irrigated, causing gill filaments to collapse and become ischemic. Indeed, all water-quality parameters should be identical to the fish's normal tank water (e.g., pH, salinity, hard-ness), and ideally water used for anesthesia