What is "betta pugnax"

Fighting \Fight"ing\, a.

1. Qualified for war; fit for battle.

   An host of fighting men.
   --2 Chron. xxvi. 11.

2. Occupied in war; being the scene of a battle; as, a fighting field.
   --Pope.

   A fighting chance, one dependent upon the issue of a struggle. [Colloq.]

   Fighting crab (Zo["o]l.), the fiddler crab.

   Fighting fish (Zo["o]l.), a remarkably pugnacious East Indian fish ( Betta pugnax), reared by the Siamese for spectacular fish fights.