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Do Neon Tetras Play Dead?

The world’s oceans are full of creatures that possess diverse, remarkable, and even entertaining means of avoiding danger or finding prey. Cuttlefish use their color-change abilities to escape hungry predators.

Sea cucumbers can forcefully eject portions of their intestinal tract to frighten off famished ocean dwellers. The deep ocean pelagic shrimp, also known as the zombie shrimp, even plays dead to avoid appearing delectable to aquatic hunters.

Fish keepers may be able to observe less obvious, but still effective examples of captive fish avoiding danger in a home tank. Hiding in tank accessories, or quickly fleeing an area of the tank are frequently used means of avoiding perceived harm for many species within the hobby.

Neon tetras, a beloved, and readily available species, dash off when sensing danger. Tetras do not play dead.

Why You Might Think Your Neon Tetra Is Playing Dead

If you discover one or more of your neon tetras resting along the bottom of the tank you should immediately remove the fish from the community. Harvest enough water from the tank to allow the removed fish to swim comfortably in another container and place them inside.

A small spare tank is ideal, but a food storage container can serve as a temporary quarantine tank in a pinch. Begin to closely observe your animal as you move back to the community tank and look for evidence to explain what has gone wrong with the health of your neon tetras.

Possibility 1: Neon Tetra Disease

Neons are speedy and small, allowing them to escape from predators quickly and hide. They do not play dead to avoid capture.

If you observe a member of your neon school exhibiting behaviors such as lethargy or remaining on the bottom of the tank, it is a warning sign of something more serious and requires quick action.

Several illnesses can affect Neon tetras.  Neon Tetra Disease presents symptoms most similar to playing dead.

First identified in neons, this disease has since been recognized as one that can affect other species. Neon Tetra Disease spreads quickly through a population. You must immediately deal with it when found.

Neon Tetras Disease can be introduced to a tank through the addition of a parasite. This parasite can hitch a ride into a tank in a few ways.

Neons are omnivorous in the wild, and would typically enjoy a treat of live food. Keepers who opt to feed their stock live food, such as bloodworms, need to make sure they are getting them from a reputable source. If not, they could introduce a parasite through this treat. 

Once ingested, the parasite can then spread to other fish through shared food, diseased fish, or consumed waste. If a sick fish is brought into an existing tank community, the other tank residents will be in danger of exposure to the parasite.

Interesting READ  Can Tetras Eat Bloodworms?

Fish subjected to Neon Tetra Disease exhibit behaviors that may seem similar to those of animals who naturally play dead. Before succumbing to the illness, a fish will begin to favor the bottom of the tank and become lethargic.

If a fish ever begins to exhibit unusual behaviors, a keeper must remove the animal from the tank and quarantine it for observation. By removing a sick fish as soon as possible, others in the tank community have a chance at survival.

While the fish may prove to be well, or simply older, removal is the safest option.

Possibility 2: Bad Temperature and Tetra Health

Upon finding a neon exhibiting behaviors of lethargy, a fish keeper should immediately examine the thermometer in the tank. Neon tetras are tropical freshwater fish from the South American countries of Colombia, Brazil, and Peru, specifically the portions of these nations encompassing the Amazon River.

neon tetra health

These equatorial locals infrequently drop below 70°F. Although some tetra species living in this environment can survive when record lows occur, neons have a more difficult time. 

Neon tetras are some of the most fragile species in the Characidae family. Temperatures that more closely mimic those found in their natural environment will help provide neons with a tank habitat that will promote good health.

When exposed to low temperatures, it will be more difficult for neon tetras to fend off illness. Tetras can also become severely stressed when exposed to poor temperatures, taxing their bodies further.

If a keeper finds a tank temperature is low, and the neons inside seem sluggish, upping the heater output should be the most immediate intervention. A sick fish may still succumb, but raising the temperature gives them the best chance for recovery.

Possibility 3: Ammonia and pH Levels In A Tank


Once incorrect temperature has been ruled out as a cause for lethargic behavior in neons, a fish keeper should then move on to evaluate water quality. The first thing to check is the filter.

A functioning filter is a must for any neon community tank. The filter helps to eliminate naturally occurring toxins such as ammonia, nitrites, and nitrates.

Without a dependable filter, these compounds can begin to build up in a neon’s tank and expose the fish to harm. A fish keeper must change their filter matter regularly to maintain water quality.

Simply checking how the filter is operating is not enough to ensure water quality. If a neon appears to be playing dead, a keeper should immediately perform a water test.

Test kits are available at all pet stores for purchase, and allow for easy water quality monitoring. Take a sample of water from the tank and add the included chemicals.

The resulting color change in the water, when compared to an easy-to-read chart, will give an accurate reading of the pH or ammonia levels in the tank. Weekly water changes of about one-fourth of the tank capacity can also go a long way in the management of healthy water quality in your tank.

Interesting READ  Will Different Tetras School Together?

Possibility 4: They Could Be Stressed

At only one and a half to two inches, neon tetras are some of the smallest species in the family. Neons’ more fragile, smaller bodies can become overwhelmed with stress response. 

If a keeper has checked water quality and temperatures, and all other fish in the community seem to behave normally, the neon that appeared to play dead may be suffering from stress.

Stress can be brought about through exposure to extreme temperatures and poor water quality, but there are other negative stimuli that a tiny Neon can find stress-inducing in a tank. Aggressive tank mates can pose a huge threat to tiny Neons.

Even without direct physical attack, a neon can become so stressed by a tank mate nipping at its fins that it can become ill and die.

If stress brought about by the tank environment was the cause of strange behavior in a Neon, it is possible that after removal from the tank, the fish may improve.

What should I do if my tetra looks sick?

A neon that has been removed from a tank because of unusual lethargy should be monitored in a quarantine tank. This fish should not be returned to the community tank unless it makes a full recovery and returns to some level of usual movement for more than twenty-four hours.

A fishkeeper may want to include an additional neon in the quarantine tank set up once the separated fish has begun to improve to alleviate additional stress. If there is no improvement, a fish keeper must continue to observe the neon, taking care to note any new changes.


How can I prevent Neon Tetra Disease or any other illnesses in my tank?

There are several steps that keepers can take to guarantee their fish will not be exposed to illnesses and infections from the outside. An important factor that can contribute to fish health is knowing that your local pet store is dependable.

When acquiring new fish, or experimenting with live food, a reputable dealer is a must. 

Even the most reliable pet store can have an issue with unhealthy stock. Fish keepers should quarantine an animal for at least 24 hours before introducing any fish to the new tank. During this period it is imperative to monitor behavior closely.

Are there missteps I can avoid to ensure a healthy tank environment?

There are errors a keeper can avoid to ensure optimal tank health. Fish keepers with a tropical freshwater tank should set a heater high enough to maintain proper tank temperatures. Monitoring water quality also goes a long way to ensuring that delicate fish like Neon tetras have the fortitude to resist illness.


Neon tetras, as delicate as they are, can be kept successfully by even the most novice fishkeepers. By taking simple steps to maintain a healthy tank, Neons can reach their lifespan potential of five years.

If you see any unusual behavior in your neons, such as behavior that mimics playing dead, quick action can save a tank community.