Betta Tail Biting

[Carlrs]

With scientific method thrown out, this myth has exploded with the help of Admins in anecdotal fish keeping FB forums such as "Fish Tank Enablers"

http://www.fish-as-pets.com/2014/10/common-aquarium-keeping-myths.html#betta

Here is an excerpt:
For starters, biting of ones self when it has some sort of irritation (itch, stress, etc.) is a warm blooded animal phenomenon.
You will not see a lizard, fish, etc. biting itself. Rather you will see these animals scratching against a rock or similar due to irritations. This is more commonly known as "flashing".
However, it is quite common for a bird or dog to literally decimate themselves over irritations or stress. Stress decimation has never been proven in cold blooded animals.

Further Reading:
Warm-Blooded vs. Cold-Blooded

Most likely the damage observed is due to poor water parameters & care, or damage from decor such as rocks. This is especially true when a current is strong and/or the fish is weak.

Here are a few recommended resources, the first is a MUST READ where following each point is a must (or at least as many points as possible). The second is just some basics to Betta care:
*A Healthy Aquarium, Disease Prevention
*Betta Profiles, Care

Often what persons have described in videos is actually healthy Bettas showing aggression attempting to bite itself, not actual stress induced biting.

Here is one such video example. This video claims tail biting, but does not show tail biting, rather just common Betta aggression whereby damage is mostly likely from impacting objects in the aquarium/bowl:
YouTube; Betta fish tail biting
OR this again showing aggression biting, not stress
YouTube; Male Betta Biting His Tail
Every other YouTube video is someone assuming their poor Betta is biting their tail, many showing Aeromonas and not treating for the real problem. This is how bad this myth has spread!!

Another point is that this myth was dismissed by most in the professional aquarium keeping industry (including in fish illness seminars I attended), it was not until the Internet that it exploded that is suddenly became truth to many via non science based blogs re-posting the same information as an attempt to explain to many what they were seeing was tail biting like one might see with a stressed bird.
Most of these blogs are regurgitating the same information (copy & paste) even the same diagram. One blog was by a friend (NippyFish) that I know was hijacked by a Russian (where I have been attempting to help her with DMCA acts that so far have gone nowhere, thanks Google), so this is far from trustworthy

An interesting point that many of these non professional based blogs have in common is they state that certain bite shapes in tail damage are proof of biting when in fact this is simply more an indicator of the pathogen. The so called "Betta biting chunk" is typical of a Columnaris infection where by chunks of tissue simply fall off.
More common though of Betta Fin Rot is a more ragged deterioration which these blogs claim (correctly) is more from fin rot. Problem is Fin Rot is not a disease per say, rather symptom (just like Septicemia or so called Red Pest). This more ragged fin damage is more common of an Aeromonas or Pseudomonas infection.

Here is one of the copy & paste pictures that these blogs have shared that I have corrected to the correct diagnosis as per known science:

Of course one might ask what does it matter?
Why getting this right matters is such myths distract from the real causes and addressing these, especially if a case of fin rot is involved.
This especially becomes critical when the fin rot is caused by Columnaris, albeit a less common cause of such damage, as Columnaris can be an aggressive infection if not addressed while the misled fish keeper attempts to address an incorrect cause.
Luckily often Columnaris is stress related, so the non experienced aquarium keeper removers the stressor and boom, they think they cured their Betta tail biting and the myth goes one!!