The Complete Guide About Over Halfmoon Betta Fish

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By Linh Nguyen Updated on 12 Mar 2023

The Halfmoon betta is one of the most visually stunning fish in the aquarium hobby and has become a popular choice for aquarists looking to add some vibrancy and color to their tanks. But have you ever heard of an Over Halfmoon (oHM) betta? 

An Over Halfmoon is a manifestation of the Halfmoon form taken to its extreme. Its tail, when spread out, exceeds 180 degrees and gives it a scalloped appearance with edges that flow toward its body. This stunning mutation also often translates into vivid coloring and patterns that stand out among other types of Bettas. 

In this blog post, we'll be taking a closer look at the unique Over Halfmoon Betta, from its origin and characteristics to how to care for them in your home aquarium. So if you're looking for an eye-catching addition to your tank, then read on to learn more about this beautiful fish!

An Over Halfmoon Betta Fish

An Over Halfmoon Betta Fish

1. What is Over-Halfmoon (oHM) betta fish?

A Betta Over Halfmoon (OHM) is a type of Halfmoon betta that has an exaggerated tail with edges exceeding 180 degrees. This creates a scalloped look to the tail, where the edges are curved and flow towards the body of the fish. Most OHMs have tails that are slightly in excess of 180 degrees, which may not be preferred by IBC judges but still exhibits a beautiful appearance. The fins on an OHM should fan out symmetrically in a perfect circle when viewed from above and create impressive ripples when swimming through water. An OHM should also have smooth, even coloration around its entire body and vibrant patterns throughout its fins. These fish are considered to be a high-end show betta, often showcased in competitions where they compete with other Halfmoon bettas for the highest marks. OHMs have become increasingly popular due to their unique beauty and graceful swimming style. 

Besides, the fish also needs to meet the criteria of a basic Halfmoon such as:

  • The caudal fin should be symmetrical.
  • The branching of caudal rays is at least 3 times.
  • Dorsal and anal fins should be in balance with the caudal fin and body.
  • The ventral fins should be as short as possible.

2. Distinguish from Halfmoon bettas

To distinguish a Halfmoon betta from an Over Halfmoon betta, you can rely on the spread of the tail. For a true Halfmoon, a 180° tail spread is required (neither excess nor shortage permitted). If the fish has a tail spread greater than 180°, it will be considered an error and classified as an Over Halfmoon.

Distinguishing an over halfmoon betta from a halfmoon betta

Distinguishing an over halfmoon betta from a halfmoon betta

3. Distinguished from Fullmoon bettas

Distinguishing an Over-Halfmoon betta from a Fullmoon betta is really simple. The Fullmoon betta is a double tail, while the Over-Halfmoon betta is a single tail.

Distinguishing an over halfmoon betta from a fullmoon betta

Distinguishing an over halfmoon betta from a fullmoon betta

4. Over Halfmoon betta facts

The Over Halfmoon betta strain is an extension of the illustrious HM fish. This means that they share a lot of similar traits, such as their natural characteristics. To sum it up: oHM and HM are almost identical in terms of behavior and appearance. Here is a quick recap.

  • Over Halfmoon Bettas have long, flowing fins and a large tail that gives them an almost 180-degree arc. 
  • They are considered one of the most impressive-looking betta fish varieties due to their colorful body, attractive finnage, and eye-catching shape. 
  • They have a lifespan of up to 3 years with proper care and maintenance. 
  • Over Halfmoon Bettas come in a variety of colors such as blue, red, yellow, green, purple, white, and even black. 
  • These bettas require plenty of space because they are very active swimmers who love to explore their tanks. 
  • They should be kept in at least two gallons of water with adequate filtration and oxygenation to maintain their health and vitality. 
  • These Bettas should be fed a variety of high-quality proteins and vegetables, including live or frozen bloodworms, brine shrimp, daphnia, and mosquito larvae. 
  • It is important to provide plenty of hiding places in their tank for them to retreat when they feel stressed. 
  • They can also benefit from regular water changes to keep the tank clean and healthy. 
  • These fish are generally peaceful with other fish species, though they will fight with other male bettas if housed together.
  • Over Halfmoon Bettas often require special treatment when breeding, and should only be attempted by experienced aquarists.
  • They are sensitive to water parameters and must have the proper environment to maintain their health.
A yellow betta over halfmoon

A yellow betta over halfmoon


After reading about the stunning Over Halfmoon Betta, it's easy to understand why they've become such a popular choice among aquarists everywhere. Their flexible fins, bright colors, and calm temperaments make them ideal for newcomers and experts alike. And with the proper care and respect for their environment, these fish can provide much joy and beauty in your aquarium. From regular water changes and temperature checks to high-quality food and plenty of security measures, you'll be able to give your Over Halfmoon Betta a healthy home where it will thrive for years to come. It's an amazing experience that will soon have you oohing and ahhing like everyone else who owns one of these aquatic pets. If you're ready to take that step and bring an Over Halfmoon Betta into your life, let me know in the comments below – I'd love to hear your story!

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