Complete mitochondrial genome of mouthbrooding fighting fish (Betta pi) compared with bubble nesting fighting fish (B. splendens).

Betta pi is the largest species of mouthbrooding fighting fish, while B. splendens is a globally ornamental bubble nesting fish. Complete mitochondrial genomes (mitogenomes) of wild individuals of B. pi and B. splendens were determined. The mitogenome sequences were 16,521 and 16,980 base pair in length, containing 37 genes with gene order identical to most teleost mitogenomes. Overall A + T content was 57.72% for B. pi and 61.92% for B. splendens. Phylogenetic analysis showed that B. pi and B. splendens were highly supported monophyletic clades. Our results will facilitate further genetic studies, including mitochondrial variations and population structure of fighting fishes.