Ontogenetic oxygen changes alter zebra fish size, behavior, and blood glucose.

Four male and four female zebra fish were crossed in all possible combinations, resulting in 389 offspring. These offspring were divided among four treatments: normoxia for 90 d, hypoxia for 90 d, normoxia for 30 d followed by hypoxia for 60 d, and hypoxia for 30 d followed by normoxia for 60 d. The effects of early oxygen environment, later oxygen environment, and genotype were then assessed with respect to zebra fish behavior, size, and blood glucose. Fish were tested in an arena where they could shoal with conspecifics before, during, and after the introduction of a novel stimulus. Blood glucose and size were also measured. Early oxygen environment influenced fish size, time spent swimming, and reactivity to a novel stimulus. Environmentally induced plasticity was predominate, with little evidence of among-sire variation for any of the measured parameters.