Tail biting is self-inflicted damage to the tail of a betta fish. Two common ailments often confused for tail biting are fin/tail rot and torn, or “blown,” fins from swimming. Blown fins is a term “associated with the curious aberration that occurs in some heavily-finned males that are swimming or flaring too hard” (Parnell, BettySplendens.com). It is important not to confuse tail biting with natural tears or with fin/tail rot, which is a fungal disease that can be lethal if not treated correctly. Tail biting is less prevalent in short finned betta fish, such as the plakat breed. The causes of tail biting are largely unknown while “some say it’s stress, others say boredom and still others think it could be hunger, pent up aggression or even hereditary” (NippyFish.net).
While it is not definitely known what causes tail biting, the behavior is generally easily remedied. Although some betta fish may be more persistent than others, tail biting can be stopped and fins will grow back with proper care. After diagnosing a betta fish tail biting, and not fin/ tail rot or merely having blown fins, it is important to first treat the wounds. Even though the fish is doing the damage to itself, the damaged area may become infected if preventions are not taken. Keeping the water warm and adding medication such as Melafix or Pimafix can help prevent infection , although medication is not necessary in most cases (NippyFish.net). It is also recommended that a betta keeper adds aquarium salt (not to be confused with Epsom salt!) to the tank for a short period of time and that water conditions are kept very clean.
Common ways to remedy the behavior include rearranging the tank, adding new hiding places, making an environment more stress free, and adding Indian Almond Leafs (IAL) to the water. Checking the tank for possible aggression enhancers can also be useful, such as changing bright lights to “reduce reflections, which may fuel…aggression” (NippyFish.net). These treatments are typically in response to the idea of tail biting being the cause of boredom or stress.
Rearranging the betta’s tank can help with stress and enrichment issues because the new arrangement can give the fish a feeling of security, such as having new hiding spots, and give it the opportunity to explore. Change objects around in a tank can also give the fish more space, which leads to more exercise. In addition to adding hiding spaces, sometimes taking some objects can help. Betta fish react differently to different objects and how they are placed. Sometimes betta keepers notice one of their fish constantly flaring at a decoration and another not leaving its side. Because they have personalities, environment preferences will vary widely. Adding the temporary presence of mirrors can also be helpful for exercise and releasing aggression (DarkmoonBettas.com).