Betta (Siamese Fighting Fish) - Behavior

Behavior

Males and females flare or puff out their gill covers (opercula) in order to appear more impressive, either to intimidate other rivals or as an act of courtship. Other reasons for flaring their gills is that they are startled by movement or change of scene in their environment. Both sexes will display horizontal bars (unless they are too light a color for this to show) if stressed or frightened; however, such a color change, common in females of any age, is very rare in mature males. Females often flare their gills at other females, especially when setting up a pecking order. Flirting fish behave similarly, with vertical instead of horizontal stripes indicating a willingness and readiness to breed (females only). In fact the fish flare their fins and gills as a sign of aggression or flirting with other fish. Bettas sometimes require a place to hide, even in the absence of threats. They may set up a territory centered on a plant or rocky alcove, sometimes becoming highly possessive of it and aggressive toward trespassing rivals.

The aggression of this fish has been studied by ethologists and comparative psychologists. These fish have historically been the objects of gambling; two male fish are pitted against each other in a fight and bets are placed on which one will win. One fish is almost always killed as a result. To avoid this, male Siamese fighting fish are best isolated from one another. Males will even respond aggressively to their own reflections in a mirror. Though this is obviously safer than exposing the fish to another male, prolonged sight of their reflection can lead to stress in some individuals. Like other fish, the Siamese fighting fish may respond to the presence of humans and become trained to respond to feeding cues (such as a hand placed over the water's surface). They are quite curious and will watch humans going about their business nearby.