With warm-blooded vertebrates, systemic and local analgesics are recommended with major surgery. Intracoelomic surgery, extensive external debridement, or orthopedic surgery warrant local anesthetics and perhaps continued oral or injectable analgesia for days to weeks. Although a benzodiazepine may not be considered a true analgesic in mammals, the sedative effects post-surgery may keep a fish from causing further injury to itself and is therefore included as a post-surgical treatment. Pre-surgical evaluation usually involves taking a history, observing the fish in its environment, gill clip/gill endoscopic exam, fin clip, skin scrape, water quality evaluation, and a thorough physical exam under anesthesia. Surgical events of one hour or more typically have increasing depths of anesthesia requiring the maintenance solution to be diluted. Monitoring the heart rate and/or opercular rate generally determines the effective depth of anesthesia. Standard companion animal spay packs usually have the necessary surgical tools for fish surgery.