Why Does My Betta Fish Look Dead? (7 Reasons with Solutions!)

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Betta fish have long been popular in the hobby, and they are continually finding favor among new fish keepers. Betta fish have bundles of personality, which is why they quickly become pets, even members of the family.  As with any pet, it can be distressing for the owner if their pet appears to be dying.  In this article I look at Why does my Betta fish look dead?

There are many reasons a Betta fish may be laying in the aquarium looking dead.  These include;

  • Resting/sleeping
  • Temperature too high or too low
  • Exhaustion
  • Ammonia poisoning
  • Pests or disease
  • Old age
  • The tank is too small

1. Resting or Sleeping​

One of the oddest quirks about Betta fish is they actively sleep! Over the last 30 years, I have kept dozens, maybe hundreds of species of fish, but I don’t think any others rested like a Betta.

Betta fish will rest by laying on their sides and they can do it in the oddest of places.  I have had Bettas which liked to lay on rocks, behind the heater, and even in clumps of plants.  It seems to vary by individual Betta, but they all seem to prefer a different place to rest.  You can even buy Betta Hammocks for them to sleep on!

When Betta fish choose to rest, they naturally stay very still and can appear to have died.  However, as a dead Betta doesn’t breathe, you can always check he is alive by looking at his gills (the slits behind his eyes).  If they are moving he isn’t dead.

2. Water temperature is too high or too low​

Despite what you may have read or heard elsewhere, Betta fish are tropical fish and they will almost always require an aquarium heater to maintain the water at a constant temperature.

If your Betta is kept in an unheated aquarium, especially a small, unheated aquarium, the temperature may swing wildly.  If you live in a warm part of the country, the daytime ambient temperature may be fine, but the chances are the nighttime temperature will drop rapidly.

Bettas need their water to be between 74°F and 80°F (23°C and 26.5°C).  Personally, I set the temperature on my Bettas aquarium heaters to 76°F (24.5°C). That way there is room for a slight variation in temperature.

When a Bettas water is too cold (or too hot) they can become stressed, and stress will kill a Betta very quickly.

If your Betta is looking like he is dead because his water is too cold, consider adding an aquarium water heater and set it to 76°F (24.5°C) ASAP.

3. Exhaustion​

Over many generations, Betta fish have been bred to have long, flowing fins.  Whilst these fins look amazing, they do make it difficult for Bettas to swim.

If we keep our Bettas in aquariums with powerful filters, the water flow may make it difficult to swim against.  If our Bettas are having to work really hard to just fight against the flow in the aquarium they can quickly become exhausted.

An exhausted Betta may well just lay on the bottom of the aquarium and look like he is dead.

If you believe your Betta may be sitting on the bottom due to exhaustion, consider turning down the filter, or changing the output so it blows the water back to a different area of the tank. 

Bettas, like almost all fish, need areas of the tank where the flow is lower and they can swim without putting so much effort in.

For this very reason, I like to filter my Betta tanks using air-powered sponge filters.  Sponge filters are great at filtering the water, without blowing the betta all around the tank.

4. Ammonia Poisoning​

On the subject of filtering our Bettas aquariums, so many people are led to believe their Bettas won’t need a filter.  Unfortunately, this isn’t true, Betta tanks DO need a filter.

When our Bettas go to the bathroom, their waste is very high in ammonia, and ammonia is toxic to fish.  Ammonia can kill a Betta, even at relatively low concentrations.

Luckily, our aquariums are full of good bacteria (often called ‘beneficial bacteria’) and this bacteria specializes in converting the ammonia is our Bettas waste, firstly to nitrite (with an ‘i’) which is less toxic than ammonia, then to nitrate (with an ‘a’) which is less toxic still.

Without a filter, the ammonia levels will literally poison your Betta, burning his gills until he can’t breathe.  At this point, he may well just lay on the bottom of the tank looking dead.

To fix the problem immediately, consider changing around 50% to 75% of the Bettas tank water with fresh, dechlorinated tap water.  Next, add a good quality, but low-powered filter to your Bettas tank.  

The bacteria in a filter takes a few weeks to establish, but once it does, your Betta will be living in much cleaner, safer water.

5. Pests or Diseases​

Although generally considered hardy fish, Bettas can occasionally become affected by pests or diseases.  Many of these pests and diseases sap the strength from the Betta, leaving it sitting, lifeless on the bottom of the tank.

The most common pests and diseases that affect Bettas are Ich (also known as Whitespot), internal tapeworms, and fin rot caused by a bacterial infection). Almost all pests and diseases will eventually prove fatal for a Betta if not treated promptly.

The first step to treating a Betta for a pest or disease is the identification of the problem. Some are easier than others.  White spots on the Bettas fins or body is easily identifiable as Ich.  White, stringy poop may be an indicator of internal parasites like tapeworms, and torn, raggedy fins may be a sign of a bacterial infection.

If you have a reliable local fish store, take some good photos of your Betta in and show the employees.  They should be able to identify the problem and recommend a suitable treatment.

The video below from Aquarium Co-Op has some information on the 5 most common Betta pests and diseases.

6. Old Age​

Many of us love our Bettas and we spoil them.  We give them perfect water conditions to live in, feed them good quality foods like Bug Bitesbloodworms, and daphnia, and we treat them with medications when they become ill.

As a result, Bettas in captivity will often live much longer than their cousins living in the wild.  Bettas have not evolved to live long lives, they have evolved to live fast, breed often, and die young, maybe all in a single season.

A Betta in captivity can live for a number of years, and as he approaches the end of his life, he may well have less energy for swimming around.  As such, he may spend a lot of time laying on the bottom of the tank looking like he is dead.

There isn’t a great deal you can do when a Betta gets this old except keep feeding it good quality foods, make sure its water is clean and free from ammonia, and enjoy him for as long as you can.

7. The tank is too small​

Betta fish are surprisingly sensitive souls, and when kept in very small tanks, which they often are, it can affect them.  

Betta fish are often recommended for tanks as small as a vase, as this simply isn’t enough room.  A Betta kept in a very small aquarium may sulk, and may become stressed.  Either can result in the Betta just laying on the bottom, looking like he is dead.

The solution here is fairly simple.  Upgrade the Betta to a larger tank.  I strongly recommend a minimum of 5 gallons (19 liters) and a 20 gallon (75 liters) tank is even better.

I have kept Bettas in tanks as small as 2.5 gallons (10 liters) and believe me it is harder to keep their water clean.  The larger the volume of water you can keep your Betta in, the easier it is to keep that water stable and the Betta happy.

My Final Thoughts on ‘Why Does My Betta Look Dead?’​

There are many reasons a Betta fish may lay on the bottom of the tank looking dead.  Maybe he is resting and maybe he is sick.  Working out which, can be the difference between your Betta doing well and your Betta actually dying.

Taking time to really observe your Betta can help work out if there is a problem, and then the best way to deal with it.

About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James