Betta Flashing: Causes, Treatment & Prevention

Betta flashing isn’t something a lot of people know about, but it’s an important behavior to understand.

It can often signal something more serious going on.

Betta flashing is characterized by frequent rubbing and scratching against items in the aquarium. Flashing behavior in bettas often indicates a health issue or elevated stress levels, so it’s critical to learn what’s causing your bettas to flash.

If issues are left untreated, it can result in the death of your betta.

betta flashing atf

Betta Fish Flashing: An Overview

Flashing is common in bettas and other freshwater fish, most often observed when the fish are ill or in poor aquarium conditions. The following behavior characterizes flashing: 

  • Rubbing or scratching themselves on items in the aquarium 
  • Jumping out of the water to experience the friction of the water’s surface
  • Swimming in bursts, especially near aquarium objects

If you notice these symptoms in your bettas, it’s crucial to have them properly diagnosed by a vet.

Flashing behavior almost always indicates a health or environmental issue.

If left unchecked, these issues can result in the death of your bettas. 

Causes of Betta Fish Flashing

Betta flashing typically occurs when the betta is ill or stressed.

Freshwater aquariums are known for their susceptibility to several parasites, including anchor worms and flukes.

Parasites can sometimes cause secondary infections, weakening your bettas’ immune systems.

Bettas are also prone to ich, dropsy, and swim bladder disease

Betta fish experiencing high levels of stress may also exhibit flashing behavior.

Stress is usually caused by issues in the fish’s environment, such as crowding or poor water conditions. 

Health Issues in Betta Fish

disease causes betta flashing

Freshwater fish like bettas are prone to various parasites and diseases, some of which can cause flashing behavior.

Here are a few potential health issues your flashing bettas may face. 


Parasitic infections are the leading cause of flashing in bettas. The most common symptoms of freshwater parasite infections include the following: 

  • Flashing
  • Clamped fins
  • Aggression
  • Lethargy
  • Lack of appetite
  • Color change or dulling

Since most freshwater parasites are microscopic, only a vet can determine whether an infection is present. 

There are a few different types of freshwater parasites to be aware of.

Anchor Worms

Anchor worms are a type of macroscopic crustacean, and it acts as a parasite in freshwater fish.

An anchor worm attaches itself to its fish host using an anchor-like appendage on their head, feeding on the fish’s blood and flesh.

Female adults lay their eggs, which hatch into free-swimming juveniles, which will later attach to a fish host. 

Betta Lice 

Betta lice are not actual lice but rather belong to the crustacean family.

These macroscopic parasites attach to a fish host to feed and eggs on hard surfaces in the aquarium.

A few symptoms of betta lice infestations include dulling color, lethargy, and flashing.  


There are two types of flukes in freshwater fish: gill flukes and skin flukes.

Both types attach themselves to a fish host to feed, lay eggs, and continue the cycle. 

Flukes are a type of microscopic flatworm, meaning they cannot be seen with the naked eye.

To get a proper diagnosis, take your infected fish to a vet with the proper equipment and expertise to identify the issue. 


Ich is frequently known as “white spot disease” due to the white spots on an infected fish’s exterior.

It’s caused by the rapidly reproducing protozoan Ichthyophthirius multifiliis, and the infection is deadly if not treated promptly. 

Betta Diseases

Common betta fish diseases include the following: 


Dropsy causes a betta’s liver and kidneys to retain fluid, resulting in a swollen abdomen.

Since dropsy cannot be cured and will result in death, practicing prevention measures is crucial. 

Fin & Tail Rot

Bacterial or fungal infections in the fins or tail cause this disease. If left untreated, the infections spread to the rest of the body. 

Hole in Head

This disease is often fatal, causing holes to form in the betta’s head.

These holes look a bit like pinholes, and their current cause is unknown. Hole in the head kills bettas quickly, usually within about five days. 


Popeye is characterized by swelling in one or both eyes. It’s often caused by bacterial infections, though tumors are another known cause.  

Swim Bladder Disease

Several potential causes of swim bladder disease include overeating and low water temperatures.

Stop feeding your fish for three days to treat swim bladder disease. This may help them reset their systems.

Environmental Stress in Betta Fish

environment not right causes betta flashing

Flashing behavior in bettas can sometimes indicate an issue with their aquarium environment.

Betta fish require specific living conditions to thrive; if these conditions are not met, they may become stressed or ill. 

Poor Water Quality

Bettas may experience environmental stress when the water quality is poor.

If the water contains heavy metals such as lead or mercury, this can weaken the fish’s immune system or even poison it. 

To ensure your bettas are living in the best possible water, take a water sample and have it tested.

If you find out the water is contaminated, take the proper steps to purify it. 

Unstable Water Conditions

Because bettas require specific living conditions, they become anxious if their environment experiences rapid change.

This might happen, for example, if you do not acclimate your bettas to a new aquarium or if any heaters or filters in the tank cease to work. 

Aquarium Crowding 

When too many fish are crowded into one tank, two main issues crop up: 

  1. Ammonia levels rise much faster, which is often deadly.
  2. The fish do not have the space or privacy they need to thrive. 

For a single betta fish, we recommend an aquarium size of 5 gallons or more. The more bettas you have, the larger your aquarium should accommodate their needs. 

Lack of Hiding Places

Bettas prefer environments with “hiding places,” such as logs to hide inside or plants to swim amongst.

Reduce the stress levels of your aquarium fish by placing decorations in the tank to give your fish their much-needed privacy.

Betta Fish Tank Maintenance

betta flashing tank clean

To keep your bettas healthy and thriving, performing regular fish tank maintenance is crucial. This consists of a few different components: 

  • Ensuring the aquarium water is high-quality and free of heavy metals. 
  • Keeping your bettas in a large enough tank to avoid crowding.
  • Performing frequent water changes to maintain proper temperature and pH parameters. 
  • Including “hiding places” and other privacy elements to ensure the happiness of your bettas.

Preventing Betta Fish Flashing

To prevent betta flashing, keep your bettas happy and healthy.

Flashing is almost always a sign that something is amiss with your fish’s health or environment.

Follow the steps below to help prevent flashing behavior in your bettas:

  • Perform frequent water changes. This keeps the water clean and makes it easier to maintain current water parameters.
  • Keep aquarium water within optimal parameters. See table below.
  • Avoid overcrowding by keeping your bettas in a spacious tank. We recommend a tank size of at least 5 gallons for a single betta. 
  • Quarantine new fish before introducing them to the tank. This helps ensure your community tank does not become infected with diseases or parasites the new fish may possess. 
  • Monitor your bettas regularly. Watch for signs of illness, parasites, or elevated stress levels, and provide treatment accordingly. 

Ideal Water Parameters for a Betta Fish Tank Include the following:

  • Temperature: 78-80° degrees Fahrenheit (25.5-27° C)
  • pH: 6.5-7.5
  • Ammonia and Nitrite: 0 ppm
  • Nitrate: < 40 ppm
  • gH: 3-4 dGH (50-66.7 ppm)
  • kH: 3-5 dKH (53.6-89.4 ppm)
  • Minimum Tank Size: 5 Gallons

Stop Flashing (In Your Betta Fish)!

Flashing in bettas almost always indicates a problem with their health or stress levels. This makes it crucial to quickly identify the issue and provide the correct treatment. 

Bettas dealing with parasitic infections will experience intense irritation, which causes them to engage in flashing behavior.

Further, poor water quality or rapid fluctuations in water parameters often result in betta flashing.

Water changes for bettas, in particular, are crucial. Check out our guide for proper exchanges at the link.

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Wesley Oaks has a background in web publishing and decided to combine his skillset with his enjoyment of betta fish. When he isn’t working behind the scenes for Betta Fish Bay, he’s homeschooling his kids and soaking up quality family time.

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