How to Know When a Japanese Fighting Fish Is Ready to Mate?

Japanese fighting fish are fascinating to keep. These small freshwater fish, which are found in the wild in Asia, exhibit unusual breeding behaviour. Male Japanese fighting fish build an elaborate nest of bubbles, into which they place each of their eggs. The female is no longer welcome after she has dropped these eggs, and is chased from the nesting site, by her partner. Male fighting fish, particularly those which have been captive bred, display vivid colors and impressive fins.

Things You'll Need

  • Pair of Japanese fighting fish
  • Breeding tank
  • Aquarium heater
  • Light weight, broad aquatic plant leaf.
  • Transparent plastic breeding trap
  • Plastic peg
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Instructions

    • 1

      Set the thermostat on an aquarium heater to 85 degrees F and place it into the breeding tank. Japanese fighting fish originate in tropical climates and are induced to spawn when the water temperature is high.

    • 2

      Place your male Japanese fighting fish into the breeding tank. Male fish are easily distinguishable by their intense colors and long, flowing fins.

    • 3

      Place a lightweight, broad leaf onto the surface of the water and check that it floats.

    • 4

      Place a transparent plastic breeding trap into the aquarium and secure it to the rim of the tank with a plastic peg.

    • 5

      Place a female Japanese fighting fish into the transparent plastic breeding trap. Female fish are not as colorful as the males and do not possess as impressive fins.

    • 6

      Allow the fish time to watch each other and to become interested in each other.

    • 7

      Wait five to seven days, which is the time is takes before the female will be ready to spawn.

    • 8

      Observe the male during this time. He will begin to build a nest of bubbles, which he attaches to the floating aquatic leaf.

    • 9

      Observe the female closely during this time. Notice if her abdomen begins to swell, which is a sign that eggs are developing.

    • 10

      Look closely at the female's vent. Her ovipositor or egg laying tube will begin to show as she gets closer to spawn. This white tube is very short and protrudes from the female's vent. The eggs are laid through this tube.

    • 11

      Look closely at the body of the female. She will develop vertical stripes on her body at this time. These bars are an indication that she is ready to breed.

    • 12

      Place the female into the breeding aquarium at this point. She should not be placed with the male prior to her exhibiting the vertical stripes, because male fish will chase and possibly hurt the female if she is not ready to breed.

    • 13

      Watch the fish during mating. The male curls itself around the female and she releases her eggs, which he fertilizes in the water. The male fish then collects the eggs and places them in the bubble nest.