Are Zebra Danios Schooling Fish?

Zebra danios (Danio rerio) are schooling fish. This fish species should be maintained in a group of at least six or more specimens. Zebra danios thrive in schools, and if kept in too small of a grouping, these fish may become anxious, prone to disease, or aggressive toward other tank mates. 

Zebra danios are highly adaptable fish that cope relatively well in almost any community tank setup. These fish are considered hardy fish and are recommended for beginner aquarists. However, they are kept in smaller groups than recommended. In that case, the fish will become timid and never reveal its true character.

Are Zebra Danios Considered To Be Schooling Fish?

Zebra danios are a species of fish that should always be kept together. They are a group of fish that are seen “hanging out” together.

The need for certain species of fish to be grouped is why these fish are referred to as schooling fish.

These fish prefer to school together when they sense danger or a threat in their environment. Schooling is a means of protection.

Zebra danios should be maintained in decent schools, such as six or more fish of the same type of species.

Six zebra danios are the smallest number that one should begin with. Housing fourteen or more is highly advisable.

The bigger the school, the more peaceful the zebra danios seem. The more, the merrier applies here.

Keeping zebra danios together in suitably sized schools will ensure your fish thrive. Your fish tank will consist of peaceful coexistence for all your hobby inhabitants.

Failure to keep zebra danios in schools will cause stress and aggression. This may cause several health issues in your fish that may shorten their life span.

Simply put, schooling fish are defined as a group of fish species that need each other for survival. They cannot be alone. Zebra danios fall directly under that definition.

Housing Zebra Danios As Schooling Fish

Since zebra danios need to be kept together in a suitably sized school, you need to consider a few aspects when deciding to house zebra danios.

Size Of The Fish Tank

Schooling fish such as zebra danios need a minimum tank size of 20 gallons. Anything smaller would not be suitable as these schooling fish need much space to roam around.

It is recommended to purchase a 20-gallon long tank instead of a 20-gallon tall tank.

Schooling fish require a more extended tank and a lot of open areas to swim back and forth comfortably.

Hierarchy Of Zebra Danios As Schooling Fish

Zebra danios need to school together in a decent size to create a proper hierarchy system. Failure to do so may cause the fish to turn to an aggressive and lousy habit of fin nipping.

This would, in turn, create issues with other community tank mates. If something needs to be corrected in the species’ school, problems will arise in the hobby.

Since these schooling fish can be hierarchal, a pecking order may appear between the fish in a school.

However, there shouldn’t be any fighting between the zebra danios, provided that the group size is appropriate.

Selecting Suitable Community Tankmates

You have to be careful when choosing suitable tankmates for schooling fish.

Zebra danios usually interact well with similar friendly fish species in the aquarium. It would be best if you found the perfect combination of temperaments to create a happy hobby.

As zebra danios are peaceful, carefree fish, one must choose similar tankmates. Selecting fish that aren’t as active and lively as zebra danios may cause anxiety for fellow tankmates.

Also, select species that are small enough not to consider zebra danio fish as their food. Try also to consider going for your classic community type of fish. Examples of suitable tankmates would be:

  • Other similar sized danios
  • Tetras
  • Cherry barbs
  • Gold barbs
  • Corydoras
  • Rainbowfishes
  • Mollies
  • Minnows
  • Loaches
  • Livebearers
  • Cyprinids
  • Platys
  • Swordtails

Behavioral Issues Of Zebra Danios As Schooling Fish

Zebra danios may display specific behavioral issues in the hobby, such as fin nipping.

This is usually associated with needing more zebra danio fish in your tank. The importance of keeping these schooling fish in large schools is once again emphasized.

The zebra danios turn to fin-nipping as they tend to harass and show an aggressive side towards other tank mates due to stress and anxiety caused by being kept in too small of a grouping.

Tank mates with long-flowing fins are possible targets of the lively zebra danio fish. Examples of these fish would be:

  • Angelfish
  • Bettas
  • Guppies

Keeping a school of 6 or more in your tank is essential to prevent fin nipping and stop your fish from acting out of the ordinary due to stress.

Zebra Danios in Front of Plants

Why Would A Schooling Fish Swim Away From Its School?

If you notice one of your zebra danios swimming away from the others, you may need to see this as a possible cause for some concern.

As schooling fish, zebra danios would be seen swimming closely together most of the time. Witnessing a zebra danio fish swimming away from the school may indicate that they are unwell.

These fish species tend to separate themselves from the group when ill. At times, these sick fish may be chased away from the school too.

It is suggested first to have a look at the water specifications inside your fish tank, such as:

  • PH balance
  • Nitrates
  • Ammonia zero
  • Nitrite zero

Under 20 ppm nitrates are considered to be good quality.

Secondly, use a water treatment option such as Seachem Prime to do a partial water change and dose with Kanaplex to treat any possible fish diseases.

Turn the tank lights out to minimize any stress and anxiety for the fish. Also, make sure that your tank flow rate is up.

Although medication is sometimes deemed necessary, high-quality water is the ideal treatment for hardy fish such as zebra danios.

Another good suggestion is to try quarantining the ill fish in a separate tank. This would be a great option if you can catch and remove the fish without causing too much stress.

You would then be able to take good care of the ill fish on its own and be in a better position to analyze and observe the progress of the illness or concern.


Zebra danios are schooling fish that need to be kept together in a school of six or more specimens. As known as schooling fish, these species need to be together in large groups for health and safety reasons. This way, zebra danios can live a healthy, happy, and stress-free life inside your aquarium.