Though they aren't able to speak (though some do vocalize) or make facial expressions, fish have many other ways of communicating about their health and feelings. This section will introduce you to the body language of bettas, so that you can better understand your fish.


  • Fins held open, but not taut
  • Strong, bright colors
  • Active, smooth swimming
  • Feeds readily

Male veiltail betta showing relaxed/happy body language. Fins are open, but not taut, allowing them to billow and fold in the water. Color is good. He appears to be swimming actively as well.

Male crowntail betta displaying bright colors and relaxed fins.


  • "Clamped" fins - fins held shut and close to the body
  • Faded, muted coloration
  • "Stress stripes" - horizontal stripes running down the fish's body
    • Stress stripes appear much more prominently in female bettas, but can be observed, sometimes to a lesser degree, in males as well
  • Lethargy, hiding, darting
  • May refuse to eat
  • See our DISEASE/ILLNESS page for more symptoms of specific problems

Female betta displaying stressed/sick body language - clamped fins, stress stripes and faded coloration.

Male veiltail betta with clamped fins and faded coloration

The pictures in the above collage are all of the same fish, illustrating the dramatic color loss that bettas, and other fish, can undergo when stressed or unwell.


  • Fins held open as wide as possible, like sails
  • Gill covers extended
    • "Beard" visible beneath chin and beside gill covers in males
    • See our page to learn more about betta¬†ANATOMY
  • Colors brighten/are vibrant
  • Somewhat jerky, rhythmic swimming patterns
    • Alternating a head on display of open gill covers, and an undulating, slow swim with the fish's side turned to you, displaying the wide open fins
  • This is a display posture used to make the fish appear as large as possible. It is used to intimidate other males when they come into contact, or it may be used as a display during mating by both males and females

A male veiltail betta flaring - gill covers are open with the "beard" membrane visible around them, and the fins are spread open as wide as possible.

Two male veiltail bettas share a securely divided tank. The orange betta on the left displays relaxed fins while the pink betta on the right is flaring, with fins spread wide, gill covers open and dark pink beard visible beneath.

"Breeding bars"/Aggression (females)

  • Vertical bars on fish's body
  • Flared fins, displaying
  • Coloration otherwise normal
  • Displayed when the female is in breeding condition OR as a sign of aggression, such as when interacting with other females.

Female betta with "breeding stripes/bars" or vertical barring visible


Note that she is also flaring.

Another female betta displaying vertical barring