Red Blood Cell Measurements in Sea Turtles

I need to determine differences in red blood cell widths, lengths, length:width ratio, and area in three sea turtle species (leatherbacks, loggerheads, green turtles). We measured 20 different red blood cells from 20 individuals per species (N = 20 red cells per individual X 20 individuals = 400 red blood cell measurements per species x 3 species = 1200 total red blood cell measurements).

I am looking to determine differences in these four parameters per species, but I believe this is some sort of mixed model analysis as we have multiple measurements (at the same time period, not across different time periods) per individual.

I predict that leatherbacks will be significantly larger than loggerheads, which will be larger than green turtles.