Fish Health Management In Public Aquaria                                                                                            Martin G. Greenwell and Allen C. Feldman   John G. Shedd Aquarium 1200 S. Lake Shore Dr., Chicago, IL     The specific challenges of the health management of a large, primarily wild-caught, multitaxa fish collection in centrally filtered, semi-closed and closed systems are highlighted. Tropical, temperate, and coldwater fish from marine, euryhaline, and freshwater environments are all represented in this collection comprising some 350 families of fish dispersed among eighty-eight life support systems. Fish system volumes range from 10 gallons to 200,000+ gallons with a total water volume for the fish collection of approximately 3,000,000 gallons. Topics to be discussed include system/tank design issues, species composition issues, strategies to obtaining healthy stock, optimizing quarantine procedures (cost vs. benefit), water quality/life support management challenges, disease diagnosis challenges, logistics of treating sick/injured specimens, and nutritional issues. Tank designs are based upon several sources of input from several parties in a team-based approach. Competing interests of animal needs, aquarist needs, aesthetic needs, and pedagogic needs often take considerable time and money to resolve. The fish health manager in a public aquarium must navigate the fine line between a cost- and time-effective focus of population health management versus focusing on individual specimens of high economic or conservation value. Mixed taxa exhibits bring unique and often unpredictable challenges in areas such as water quality management, disease prevention, differential drug sensitivities, predation and territorial behavior (intra- and interspecies aggression). Accurate ante- and post-mortem diagnostics depend upon the training and/or experience of the diagnostician. Nutritional issues can present many challenges. Oftentimes, the natural diets of the myriad species exhibited are either unknown or incompletely known. Specialized feeders can be particularly challenging to feed. In the case of some dietary specialists such as obligate corallivores, captive maintenance is all but impossible.