Yahoo Answers is shutting down on 4 May 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

K4TE asked in PetsFish · 1 decade ago

Fish Chasing Another Fish?

I have 2 regular goldfish in my aquarium, they are all that is in the tank, no other fish.

I have one which is about a cm or two longer, and its constantly chasing around the smaller one.

They have been together in the tank for months not and ive only just noticed it happenin more this past week.

Could there be any reason for it?


oops ignore the random 'not'!

Update 2:


ye well its only just started happening, they were fine before

11 Answers

  • Anonymous
    1 decade ago
    Favourite answer

    Does the fish doing the chasing have white spots on his gills? Is he driving his nose in the rear end of the other during the chase? If so, this is spawning behavior. Summer weather has probably increased the temperature of the water in their tank, triggering spawning rituals because your fish sense its "spring season." Try reducing the amount of light the tank gets during the day, and move it away from any windows in your house. Running an electrical fan near the tank for a few hours a day will also help. Spawning behavior generally will not hurt the fish being "pursued," but keep an eye out for signs of exhaustion, such as resting at the bottom of the tank or rapid gill movement. If the little guy is getting overwhelmed, purchase a temporary divider for the tank until you are able to regulate the light and temperature.

    If the meanie fish is actually nipping at the other fish, this is aggressive behavior that can harm the smaller fish. You need to solve this by either separating the fish or buying a larger tank so the meanie fish feels less of a need to defend his territory.

    In either case, it would be an excellent idea for you to add a tank ornament or two that would provide spaces for the little guy to hide out and rest.

    Source(s): I have four goldies, two of which are ever-horny males!
  • Anonymous
    1 decade ago

    This Happend To My Fishes Last Week!

    I Would Separate Them Like Tonite, Because The Bigger One Might Be "Bullyin" The Smaller One :O

    Thats What Happend To Mine.. And The Smaller One Of The Two Died The Next Day :(

    So Seperate Them, And If The Little One Seems Alrite (Like Its Normal Self..No Teeth Marks On Fins Etc), Then Go To The Aquariam Shop Were You Got Them From For Advice :)

    Or They Might Be Matin.. Which I Thort Mine Was Doin ;)

    Still Though I Would Seperate Them Just Incase One Has A Disese Or Somethin ;) Before Goin To Your Aquariam Shop :)

    Goood Luck :)

    Ly x

  • 5 years ago

    Hi CT, I think what you're seeing is normal mating behaviour. Have a look at the fish doing the chasing-chances are he has tiny white specks all over his gill covers & perhaps along the front rays of his pectoral fins & the semi-circular plate around his eye too? These are called tubercles & the he uses them to rub against the flanks of the female to stimulate egg laying. Often it can get quite boisterous & go on for hours, especially with larger fish & sometimes minor damage may occur like missing scales or split fins (& not just the females!). Make sure you have provided some places in your tank for the females to rest & hide. By the way-I wouldn't leave it too long to build that pond otherwise you may need a 200 gallon tank sooner than you think!

  • 1 decade ago

    The larger one is just being a bit of a bully.

    This happened to my two goldfish when they were real little too, but now, after a few years, they have bred in the tank.

    I have a spare tank with little goldfish babies.

    A goldfish that is only a centimetre long is way to young to breed. Goldfish need to be at least a few years old. The male will develop white spots on his gill plates and the female will become rounder in her abdomen. My fish were around 10 centimetres long when they bred.

  • Anonymous
    1 decade ago

    could be boredom, how big is your tank? 2 common goldfish need a large tank of 55+ gallons at least. it could possibly be mating behaviour as males do chase the females nudging them to try to ecourage them to a plant to lay eggs. i dont know, i dont think you should separate, goldfish enjoy company, just add lots of plants etc, fake or real and they will be fine.

  • Anonymous
    1 decade ago

    Are you sure they aren't Betta fish or known as Siemese Fighing Fish? That usually happenes with Siemese fighing fish. If it isn't then maybe you should just try sepperating them for a while, then bringing then slowly together again.

    Hope I helped, & good luck!

    ~Nina G.

  • 1 decade ago

    The male is trying to mate with the female

    And he will bang on an on and on the female though is happier with much fewer matings so she chooses to run instead of mate

  • 1 decade ago

    a cm or two would be impossible for mating this should be bullying it is common just observe further they must not have enough food or your tank is too small.

  • 1 decade ago

    I think those two fish don't go together one might be agressive and the other is calm. Seperate those two fish

  • 1 decade ago

    i would suggest boredom is the answer

Still have questions? Get answers by asking now.