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? asked in PetsFish · 10 years ago

why is my male killifish attacking my female?

they are both Golden Wonders. I am fearful that my male is going to eventually kill my female.

he used to be by himself (except for Kuhli loaches). I added a juvenile female Golden Wonder a week and a half ago, and he seems to be bullying her, plus hitting her with his head a lot. Anybody know why? I was told the males only show aggression towards other males. I thought he'd like a female in the tank with him (it is a 20 high/24 long/15 gal) b/c of how much he was staring at his own reflection like it was another killi. She is now showing signs of fin damage and it also looks like she has lost a few scales. She seems very stressed. I am watching my male go after her unrelentlessly until he tires. After he takes a break, he resumes until he tires again. At first I thought it play, but, not now. He will corner her and not let her go anywhere, chase her, head butt her and more. He seems more interested in her than eating and tries to stop her from eating, but, she manages to eat, anyway. I have tried holding her in a net so that the male will eat, but, all he does is stare at her in the net. Any ideas on why this is happening and what to do?


positive it is a female, and as I said above, she is a juvenile, so she is not ready for mating, yet. I think perhaps my male is just used to being the only killi in the tank (he has not, however, been the only fish, as I have had 3 kuhlis in with him) and perhaps just does not know how to behave due to being the king of the tank for so long. He is just over a year old and has never been exposed to any other killis (not even at the pet store). I had him with zebra danios when i first got him, but, got rid of the danios b/c they were too aggressive with each other and stressing my killi out. Now it's HIM who is stressing the other fish (including the kuhlis now b/c of his constantly chasing the female killi). i do not have another suitable tank to put either of them in. I was really hoping (and still am)n that they can live peacefully together.

Update 2:

could I try A screen or do you think it will make things worse? my male is used to having lots of space and putting in a screen will sure cut down on his territory

3 Answers

  • 10 years ago
    Favorite Answer

    2 killifish are the only fish in that 20 gallon?

    Are you positive its a female?

    With any fish its recommended to keep a male with multiple females (3-4)

    It sounds like he is being territorial add alot of hiding places and live plants especially moss.

    Source(s): 8+ years
  • Anonymous
    10 years ago

    maybe you should try putting him in a smaller tank next to hers quite close so they can see each other and gradually try putting them back together. This worked for my dads goldfish who kept attacking each other. But for the females sake i thin you should separate them ASAP.

    Source(s): Familes Method x
  • Anonymous
    10 years ago

    i don't think he is attacking her (reproducing)?

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