I mentioned in one of my first posts that my plan is to feature a new betta fish every couple of months or so, to help you identify them more easily. I’ve already started doing that but I just realized that it might be a good idea to post some information on the betta fish anatomy to make it easier for you to pinpoint the differences between the different betta fish out there.

Betta Fish Anatomy

To start off, I though it would be handy to show you the following diagram:


I’m not going to get into details about the internal stuff too much, since like most fish, bettas have a stomach, liver, brain, anus, etc. I’m more interested in the exterior parts of the betta fish and what makes it tick.


As you can see in the picture above, all bettas have these common fins:

  • Dorsal fin – This fin is located at the top of the betta. This fin keeps the betta stable in the water and allows it to swim straighter.
  • Caudal fin – Basically, this is the betta’s tail and it is the main piece of the puzzle when trying to identify a betta. This fin is what propulses the betta forward when swimming.
  • Pectoral fins – These are small fins located on both sides of the betta, near the gill covers. You’ll see them move around when the betta is idle in the water.
  • Anal fin – Located at the bottom-most part of the betta. Again, it is used for stability.
  • Ventral fins – Located at the bottom-forward portion of the betta. They are used for steering.



Gills / Labyrinth Organ

Like all fish, bettas have gills that are located on each side, which let them take in oxygen from the water. They also have a “Labyrinth Organ” which basically lets them breathe air from the surface of the water.


Bettas don’t have eyelids so when they go to sleep, they won’t blink or close their eyes. Apparently they are also near-sighted so they only see things a few feet away, or closer.


Unfortunately, this is pretty standard and I have nothing much to say about it, other than a betta has one.


A betta’s “beard” is a membrane, which is found under the gill plate cover. When the gills are closed, this membrane kinda looks like a beard. Male bettas will often open their gill plate and membrane to other betta’s, in an attempt to scare any foes. (For more on the differences between female and male betta fish – refer to our post “Can You Tell the Difference between A Male and Female Betta Fish?“). Since I’m a huge fan of watching informational videos, I thought I’d share this interesting video that I came across where you can see this happen:

I think I’ve covered most of the betta fish anatomy, but if you think I’m missing something important, please let me know and I’ll add it! Thanks for tuning in.

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