will siamese fighting fish attack guppiesThe aim of this study was to examine the consequences of alternative concentrations of sertraline HCl on aggressive behavior of Betta splendens male fish. It was concluded that sertraline added to aquarium water in the dose of 0. 4, 4. 0 and/or 100. 4 µg and then times higher. Sertraline caused a periodic, and infrequently even total weakening of the male male type fight, which was a common trial utilized in ethological research on the Siamese combating fish.