Although their faces might take on an expression of pure anger, bettas are happy fish that show off their colors and swim blissfully around their tanks, if provided with the right conditions. If your new tank isn't up to your betta's standards, she'll show her displeasure most often through her appearance.
Look at the body of your betta for horizontal stripes and faded colors. When your little swimmer becomes stressed, her vibrant colors can fade, and horizontal dark- and light-colored stripes appear on her body. These are known as "stress stripes." Her fading colors are sometimes difficult to spot, but the stress stripes are very evident. Vertical stripes do not indicate stress; they appear when a female is ready to breed or is acting aggressively.
Look for bubbles that form together on the surface of the water. The formation is known as a bubble nest, and sometimes plant litter can be a part of it. Male bettas are usually the ones who make bubble nests—even without a female friend—because that's where they guard the eggs the females lay. Female bettas sometimes make bubble nests, but more often leave the males to do the dirty work. Unhappy bettas usually don't take the time to make bubble nests.
Watch for your betta to dart after food immediately after it falls into the tank. Bettas are voracious and vicious eaters, rarely leaving even the tiniest crumb. Stressed bettas eat less regularly and often swim right past new food.
Check to see if your betta is out in the open or often hiding. Happy bettas enjoy being the focal point of attention, and will flaunt their colors and fins all day long. Unhappy bettas go into seclusion, often hiding in the corners of the tank or in plants and other decorations.
Watch your betta as she swims. Bettas enjoy life when they're not blown around by the filter. Stress stripes almost always appear when a fish cannot swim on her own, and they'll often hide from strong currents. Remedy the problem by using an adjustable filter and setting it to a low flow setting.
- Aggression is not a symptom of an unhappy betta, but a product of the betta's personality. They typically do not enjoy the presence of most fish and will attack them if placed in the same tank without a divider.
- Some bettas are stressed out extremely easily. If you've only had your betta a few days, she may show signs of stress when you walk past her tank and open her lid. She'll adjust to her surroundings and stop showing signs of unhappiness within about a week or two.
- Medical conditions, a lack of space, unhealthy water, poor water temperature, other tank inhabitants and excessive noise contribute to an unhappy betta. Although they're sold in tiny cups, they are much happier in larger tanks. Two gallons will suffice, although they certainly don't mind something even larger. Water tests (many pet stores will do these for free) and weekly water changes help ensure the water is healthy.