How would you know if your blue betta fish is dead? 

In this blog, we will discuss dead blue betta fish and various reasons related to the same.


In this blog

  • What does a blue betta fish look like when it’s dead?
  • What kills a blue betta fish?
  • Summary 
  • Frequently asked questions

How would you know if your blue betta fish is dead? 

Blue bettas look mesmerizing when they swim in the tank by showing their beautiful fins. It is a treat to watch this beautiful creature in your home aquarium, as they come under the endangered category in their wild habitat due to human activities. If you have a blue betta fish or any captive-bred betta variety, you are very lucky.

I will list two conditions here, and explain why both are true. You’ll get a sense of what went wrong and how you can address it in the future.

If you just got a new betta fish, you must be excited to care for and feed them. When you wake up the next day and realize that your fish is dead, what might be going through your mind?

And if your one year old blue betta dies all of a sudden, it must be shocking but there are few valid reasons why they died the next day or all of a sudden after one year or so.

To find out all the reasons, we’ll discuss more details in my blog. I’m sure you’ll figure out why your beautiful and active blue betta died in your tank.

What kills a blue betta fish?

In this section, we will discuss in detail what kills a beautiful and healthy blue betta fish.

  • Improper acclimatization or no acclimatization
  • Poor water condition
  • Very low temperature or temperature shock
  • Poor tank condition
  • Aggressive tank mate
  • Overfeeding
  • Infections
  • Small tank size
  • Wrong filter size
  • Sudden and large water changes

Blue betta fish died due to Improper acclimatization or no acclimatization

If you have bought a new blue Betta fish, you must acclimatize it before you add it directly to the new aquarium. Acclimatization gives them time to adapt to the new water condition and prevents them from getting water shocks.

The new Betta fish has been adapted to the aquarium shop water conditions and before entering the new tank, it is important to acclimatize it. 

If you don’t know how to acclimate a new fish, you can check the videos on Youtube regarding the same. Several videos can help you to acclimate a new blue Betta fish.

Blue betta fish died due to poor water condition

Bettas are very hardy species and are known for surviving even in harsh conditions in their natural habitat. Being hardy doesn’t make them able to sustain in poor water conditions. 

Bettas survive well in ideal water parameters and fluctuations in water parameters can make them sick and if you don’t monitor your bettas on a daily basis, your bettas will die early.

Blue betta fish died due to very low temperature or temperature shock

Blue betta fish like their cousins are tropical species and survive well in warm water conditions. If you keep them in tanks without a heater or do not maintain and monitor the ideal temperature in their tank, your bettas will die due to colder temperatures. 

Colder temperatures make them lazy and weaken their immune system and make them more susceptible to various diseases.

Blue betta fish died due to poor tank condition

If you are getting a fish for your aquarium, it is your responsibility to keep the tank clean by removing debris, leftovers, and other biological waste which could harm your fish. It is essential to keep the tank clean so that your fish can stay healthy and live a long life.

If you don’t clean the tank regularly and allow biological waste to accumulate, your fish will not feel safe and may not be able to survive. Getting a fish is easy, but keeping them healthy and happy can be tricky. 

To avoid unexpected shocks, you need to plan ahead and make sure you’re doing regular maintenance tasks like cleaning your tank and changing your water regularly. If you don’t do something vital to the well being of the fish, they’ll soon die of negligence and poor tank condition.

Blue betta fish died due to aggressive tank mate

Deaths due to aggressive tank mates are less because bettas don’t fit into community tanks and especially male bettas prefer to live in solitary tanks due to their aggression and fighting tendencies.

If by any chance you keep your betta fish in a community tank with other fish species or their kind, they end up fighting with each other and if male bettas are involved they can kill each other to death. In the wild, it is easy to escape but in small spaces, it’s difficult to escape, so one male betta gets killed in such confrontations.

It is advised to never house male bettas with other male betta and it would be better to never keep them in community tanks too. Male bettas don’t belong to community tanks. Female bettas can tolerate each other, male bettas, and other fish species and can live in community tanks. 

If you don’t want your beautiful blue male betta fish to die, house them in solitary tanks to avoid such gruesome fights.

Blue betta fish died due to overfeeding

Bettas are known as greedy eaters by betta keepers or betta breeders because they eat whenever you feed them. They don’t mind eating anytime. It is your duty as a responsible betta owner to feed them moderately. If you overfeed your betta fish they get susceptible to a variety of digestive disorders like constipation, bloating, swim bladder disease and many to list down.

There is no cure for swim bladder disorder due to overfeeding. So if you are feeding your betta fish, feed them wisely and in moderate quantities. Excessive eating or underfeeding both are dangerous for your blue betta fish and can make them sick.

Always feed your adult betta fish twice a day and betta babies thrice a day. Keep the tank cleaning by removing the leftovers using a siphon every day to avoid ammonia spikes.

If you are away or don’t get time to feed your betta fish then install an automatic food dispenser to feed your betta fish on time. Automatic food dispensers release food in moderate quantities without overfeeding and underfeeding.

Blue betta fish died due to infections

Blue bettas can succumb to various infections due to poor water quality, unhygienic tank environment, low temperatures, parasitic or bacterial infections due to a new fish (without quarantine), and various other reasons.

If you want to avoid infections:

  • Maintain pristine water conditions.
  • Keep the tank clean.
  • Remove leftovers and other waste every day.
  • Quarantine new fish at least for 2 weeks in a separate tank.
  • Maintain and monitor tank temperature everyday.

Blue betta fish died due to small tank size

Blue betta fish like their cousins need a minimum tank size of five gallons to move freely in the aquarium. Providing the right aquarium size is directly proportional to their growth,development, and longevity.

If you house your single blue betta fish in anything lesser than five gallons, your betta fish will die due to lack of space and suffocation. If you want to enjoy this beauty, kindly house them in a spacious tank in which they can move freely and happily.

Bigger is not always better, but the right aquarium size is best for aquarium fish to survive. A wrong size will always harm your fish.

Blue betta fish got stuck in the filters and died

Aquarium filters are essential for removing impurities and keeping the tank environment clean for fish. Installing a filter in your betta tank is a good idea, but you have to make sure the filter doesn’t suck your bettas in.

Some bettas hide behind filters when they feel threatened or stressed. There is a way to avoid this problem by installing a filter that does not suck your bettas in.

Blue betta fish died due to sudden and large water changes

Water changes are an essential ritual of keeping a fish tank clean and healthy. Fresh water is added to replace the dirty water, to keep the fish happy and healthy. However, making large water changes without proper planning can stress your bettas and lead to their death.

The main reasons why bettas die after sudden and large water changes is the water’s chemistry. Your blue betta fish has adjusted to the old water chemistry and beneficial bacteria. If you suddenly change the water in your aquarium without giving your bettas time to adjust, they may not be able to tolerate the new water chemistry.

Instead of doing sudden and large water changes, you can plan a week before to do water changes in their aquarium. Doing partial water changes, by acclimatizing blue betta to the freshwater and retaining the beneficial bacteria can save your blue betta from such water shocks.


Betta fish are hardy species and survive well under all conditions. They can adjust to a variety of water parameters, but if they are kept in poor water conditions, low water temperatures, or kept in an uncomfortable position for long, they will die from stress and various other infections.

To keep your betta fish healthy and happy, you need to give proper attention and care and replicate the same condition in their artificial environment to make them feel safe and home away from home.

Frequently asked questions

Do blue betta fish die when the temperature drops below a certain point? 

Yes, blue betta fish can’t tolerate cold temperatures and will die if kept at such cold temperatures.