Results from analysis of Relative Synonymous Codon Usage (RSCU) of the mitochondrial genome of Acheilognathus barbatulus. Codon families are plotted on the x-axis. The label for the 2, 4 or 6 codons that compose each family is shown in the boxes below the x-axis and the colours correspond to those in the stacked columns. RSCU values are shown on the y-axis.