Betta akarensis Regan, 1910 BE

Betta pugnax (non-Cantor): Eden, 1984: 188 (Brunei, from almost stagnant pools in coastal forest areas to gently flowing rivers such as Sungai Lumut).

Betta climacura Vierke, 1988: 336 (Belait district: Rampayoh).

Betta akarensis Regan, 1910: Kottelat & Lim, 1995: 248 (Belait district) ; Parenti & Meisner, 2003: 47 (upper, middle and lower Belait); Tan & Ng, 2005: 67 (Bandar Seri Begawan: Mentiri Waterfalls, Sungai Mengkubau; Tutong district: Lamunin, Sungai Ratuan Uluh, Tasek Merimbun, Sungai Merimbun and tributaries; Logon Uluh Boyoh; Belait district: Sungai Melilas and tributaries, Seria, Sungai Liang, Sungai Ingei and tributaries, Sungai Jaung, Sungei Sepan, Sungai Mau); Sulaiman & Shahdan, 2003: 66 (Tasek Merimbun); Sulaiman & Shahdan, 2007: 29 (Tasek Merimbun).