Cardinal Tetras

Discussion in 'Community Tropical' started by Megan, Mar 18, 2016.

  1. Megan

    Megan Executive Board Staff Member

    I have 9 cardinal tetras that I've decided to try and breed. I did a little reading and it sounds like I need:
    RO water or rain water
    A small tank with about 6" of water
    A mop

    I read I should condition the fish in one tank and then pull them and put them in the small breeding tank when I have gravid females. Daily water changes and no feeding the adults while they are in the breeding tank. One source said they should spawn in 2-3 days. They also suggested an anti-fungal. Would Methylene blue be okay? Now I'm blanking on what they said about temp. Does 82 seem right?

    Does this sound right?
    Dave likes this.
  2. tjudy

    tjudy Executive Board Staff Member

    Challenging... Awesome!

    The best results I had with cardinals was to spawn them in pairs in very small tanks with a false bottom. A 2.5 gallon will work. Cut a piece of needlepoint mesh the same length as the tank and about 1.5" wider. Bend this sheet into the bottom of the tank so that the mesh arcs up off the bottom. Use a little java moss over the mesh. Not much is needed. If you do not have java moss, use a very sparse yarn mop... maybe only 10-15 strands. You do not want the eggs to get suck in the mop. Fill the tank 1/2 full with straight RO or filtered rain water. No heater if the room is in the 70's. I think over 80 is too warm. Place one pair in the tank in the late afternoon. Let the room stay dark overnight. Turn on the lights in the room (not a light directly over the tank) in the morning, and use a flashlight to look under the mesh for eggs... they will look like small, clear marbles. Sometimes cardinal tetras prefer to spawn in the dark. If there are no eggs, leave the lights in to room on (not directly over the tank), and check again later in the day. If the pair will spawn they will do so within 24-36 hours. If they do not spawn, try a different pair.

    When you see eggs, remove the pair and the mesh. Leave the moss/yarn. Add several drops of methylene blue to darken the water. Darkness is important to developing eggs of cardinals and neons. I would even cover the tank (all sides) with something to block light. Look for free swimmer fry after 2-3 days. Start feeding with heavy use of paramecium. I pour in about 1/2 a culture, cover the tank again and leave them alone for a few days. The paramecium will live a long time. After a couple days I check on the fry. I add RO water to the tank to fill it up to 3/4 full instead of doing a water change. After a few more days I will add more paramecium and fill the tank up. After about a week the fry should be noticeably larger, and may even start showing the blue. When that happens they are large enough to do a water change (20-30% with aged water), they can handle light now and can probably eat bbs.
    SteveS likes this.
  3. Megan

    Megan Executive Board Staff Member

    Thanks so much for all the detailed help, Ted! I can't wait to get started.
  4. Marine590622

    Marine590622 Advisory Board Staff Member

    Good luck.
    Megan likes this.
  5. Megan

    Megan Executive Board Staff Member

  6. kyzwicker

    kyzwicker New Member

    How do you tell a male from a female
  7. Megan

    Megan Executive Board Staff Member

    Good question. I think they look pretty much alike, too. I've been told the females are bigger and more rounded. I think I've only got one female in my group of 9 based on that. Hope she is a fertile little thing.
  8. Marine590622

    Marine590622 Advisory Board Staff Member

    Wikipedia says

    The blue band along the side tends to bend upwards in females. Mature females will be more full in the belly than the males, especially if they have become gravid
  9. Megan

    Megan Executive Board Staff Member

    That's very helpful, thank you!
  10. fishlady

    fishlady Executive Board

    Did you ever have any luck with this?
  11. Megan

    Megan Executive Board Staff Member

    I never pursued it. :(

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