Making a Hybrid

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Author: Crystal Beran

Grade Level: 5th - 8th; Type: Biology


Create a hybrid species of fish.

The purpose of this experiment is to take fish of two different species in an attempt to create a hybrid of the two.

Research Questions:

  • What types of animals have successfully bred with other species in the wild?
  • What types of animals have been successfully bred to form hybrid species by humans?
  • What types of animals have been genetically modified to form hybrids?
  • Why are most hybrids incapable of breeding?

Hybrid species do not occur often in nature, though there are a few known instances. Usually, hybrids are created with the help of humans. Hybrid animals are often useful to us in some way, such as the hybrid cross between a horse and a donkey known as a mule. For many species that are capable of creating a hybrid, the offspring are unable to breed. This helps keep a species from being polluted with the DNA of another species. Occasionally, though, the hybrid is able to breed, though it will sometimes have difficulty doing so. 


  • A 5-10 gallon aquarium with a heater and filter
  • 5 male guppies
  • 5 female endlers
  • Aquatic plants for the fry to hide in
  • (optional) digital camera
  • (optional) an extra aquarium

You can borrow a tank from a friend or science teacher if you don’t want to purchase one. Guppies and endlers can be bought from a pet store but you’ll need to make sure that you get true endlers. Check the shape of the tail that it is round and short. 

Experimental Procedure:

  1. Set up the aquarium and get it ready for the fish.
  2. Place the fish in the tank.
  3. Feed the fish daily, as the instructions on the food say.
  4. Take daily observation notes, checking the fish for signs of pregnancy.
  5. Guppies and endlers give birth to live young. Gestation is generally about a month. With 5 males and 5 females in the tank, there is a high chance that the fish will successfully breed within the first month.
  6. Make detailed observations of the young that are born.
  7. If you have an extra tank, you may want to move the young so that their parents don’t eat them. Alternatively, make sure there are plenty of places for the fish fry to hide.
  8. (optional) Take digital photos of the young.
  9. (optional) As time allows, you can attempt to breed the hybrid fish to find out whether they are able to produce offspring of their own. 

Terms/Concepts: Hybrid; Species; Genetic modification; Artificial insemination; Viable; Infertile


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