Two groups of juvenile summer flounder maintained a 5°C were experimentally infected with the hemoflagellate Trypanoplasma bullocki. Another group maintained at 5°C was left uninfected. The uninfected group and one infected group were then subsequently raised to 12°C, 18°C and 24°C for 2-3 weeks at each temperature. The other infected group was maintained at 5°C for the duration of the experiment. At each temperature seven fish in each group were sampled for the presence of trypanoplasms; hematocrit and hemoglobin levels were also measured. In addition, plasma incubation tests were run to detect the presence of neutralizing antibodies against the trypanoplasms. The results of the experiment will be reported and discussed.