Aquatic hypoxia, or low dissolved oxygen, is a growing environmental concern and has detrimental effects on many fishes. Research on fish responses to hypoxia includes whole animal studies as well as organ culture systems. In this thesis, the gulf killifish, Fundulus grandis, was used to determine the interaction between hypoxic exposure and four common euthanasia techniques on selected blood and gill variables and to develop an in vitro gill incubation system. Euthanasia techniques had differential effects on blood and gill, with the common fish anesthetic MS-222 having the greatest effects, but none altered the response to hypoxia. During the development of gill culture, the highest gill viability was measured in isosmotic seawater medium and shorter incubation times. This study provides insight into the applicability of different euthanasia techniques in hypoxia research, as well as preliminary observations on an incubation system for isolated gills.