Sexing Goldfish- Differences Between Males and Females


By Jamie Boyle

Goldfish sexing is what most aquarium or fish pond hobbyist would like to know sooner or later. Goldfish breeding is the answer why. As people get more into their hobby they would eventually like to see their fish breed.

Here I am going to tell you and show you the differences between male and female goldfish.

Female Goldfish

1. Females are generally bigger then the males and are they’re more plump. The reason for this is that there abdomen is all full of eggs when it comes time to breeding.

2. Females abdomen is also more soft and squishy then of the males.

3. They also have rounded and shorter pectoral fins.

4. Females also have a larger rounder anal opening with it slightly protruding as well.

Male Goldfish

1. Male fish develop breeding tubercles on their gill plates which are most commonly mistaken for the goldfish disease commonly known as Ich. They also get these small white pimple like spots on their outer ridge of their pectoral fins as well. These breeding tubercles appear during spawning time showing they’re ready to breed.

2. Males also have larger longer pectoral fins as well. The pectoral fins are the ones right underneath their gills.

3. They also have a much firmer abdomen then the females.

4. Males have a smaller more oval anal opening then the females.

5. Males are more torpedo shape then females.

These are how to tell the differences between the sexes of male and female goldfish. Here is one of the biggest ways that you can tell as well is when breeding begins to happen you will see the males chasing the females. This is a sure way to tell the differences whether it’s a boy or girl. It’s much the same as real life dating the men usually chase the women :) I will later add some photos of the breeding tubercles of males and pictures of females as well for everyone to see the differences.



37 comments on “Sexing Goldfish- Differences Between Males and Females

  1. kaegibunch on said:

    we are having trouble determining the sex of our goldfish…we tried to look for the traits of each sex but we are a bit confused..we could only identify to of our 5 fish…because one is relentlessly chasing the other,lol. we have just put in a live plant that reaches to the top of the water in the tank, as we were told to do by a local fish store. so can u please show some pictures on this site of females vs. males so we can compare them to our own fish? thank you kindly, the KAEGI FAMILY

  2. Water Lily Gardener on said:

    Determing the sex of goldfish is quite easy actually. You’ve already seen the males as they’re the ones chasing your female goldfish. You can tell by your goldfish behaviour as they will court the female goldfish.Males also have like pimples on the gill plates. Also when looking from above the females are broader while the male goldfish are more slender like a torpedo.I will place pictures on here shortly of female goldfish and male goldfish so you will be able to see. Also the male vent is concave when you look under your goldfish, this is a way to tell as well. While the female goldfish vent is protruded. I will show you shortly so you will see.What happens to when goldfish spawn the male actually nudges the sides of the female causing the eggs to be released and then the male goldfish fertilizes them at the same time. Neat to see I will try and video the spawning process here in the next 2 weeks so you will see their breeding behaviour.Need anymore help in determining the sex of goldfish please write me anytime.Sincerely,Jamie BoyleThe Goldfish Guy

  3. Jami on said:

    My fish is very plump and has white spots. It also stays at the top of the tank. Is there a reason for this.

  4. Jami on said:

    My fish is very plump,has white spots, and stays at the top of the tank. Is there a reason for this?

  5. Anonymous on said:

    I am new at having comets and have set up a small pond seven days ago.I currently have seven small comets who swim only in the bottom of the fish pond and do not surface to eat.Any suggestions?

  6. I was just going to ask what it meant when one fish chases the other. However, it always looks like my “chaser” fish is snapping/biting at my “chasee” fish. Is that part of the courting process?My other question is a little irrelevant but, I have four comet goldfish and it seems everytime I glance at the tank they are at the top of the water skimming the surface. Is that normal as well?

  7. Jamie Boyle on said:

    Hi Jami,Your goldfish could be ready to lay eggs if she is plump.The white spots could be one of two things:1. Your goldfish has white spot disease to learn more on this go to white spot diseases known as Ich2. The goldfish who has white spots they are called Breeding Tubercles on goldfish not white spot disease (ich). This is a sign of breeding and spawning in goldfish to happen soon.Check out my other two blog posts I made about this so you can learn more about goldfish breeding.Sincerely,Jamie BoyleThe Goldfish Guy

  8. Jamie Boyle on said:

    To the person with the seven comets in your goldfish pond.When you introduce goldfish to a pond they need time to get used to their new environment and home. It can take some time to get used to. Just give your goldfish some time and very soon your goldfish will be coming up to the surface pretty much feeding right out of your hand.Your goldfish are fine so nothing to worry about. They’ll soon get used to their new pond that you built and after a while you may have some goldfish breeding going on this summer too. Breeding goldfish is something all new pond owners look forward to down the road.Let me know how your goldfish are doing.Sincerely,Jamie BoyleThe Goldfish Guy

  9. Jamie Boyle on said:

    Hi Pam,For your first goldfish question, yes that is part of the whole goldfish breeding and spawning process. The male will court the female nudging her until she releases her eggs, this whole process may take several hours. When the male nudges the female it causes her to release her eggs and then the male goldfish fetilizes with the milt (sperm) he releases at the exact same time. This is part of the process in goldfish spawning the courting process.As far as your 4 comets that you have that keep coming up to the surface of the water may indicate a lack of oxygen.Does your aquarium have a filter and a air pump? Also you water quality may be bad.I suspect a lack of air is why they would keep skimming the surface.Get back to me on the above goldfish question concerning your aquarium and I will try and help figure this out with you.One last thing if your water quality is bad such as nitrite it can cause nitrite poisoning where it destroys gill filaments causing your goldfish to be unable to process oxygen. This makes it harder for your goldfish to absorb the oxygen from the water. Check your water quality for sure for PH and Nitrite for sure.Talk to you soon, PamSincerely,Jamie BoyleThe Goldfish Guy

  10. Anonymous on said:

    himy fish has like a pinkish mark on it’s kinda face i’ve never seen it before untill last week. it still swims but i wondered what the marke is

  11. Jamie Boyle on said:

    The pinkish mark that you see on your goldfish I bet is mouth rot. Mouth rot and ulcers on goldfish often occur when there are too many aeromonas and pseudomonas present in the water causing ulcers to begin.You will need to treat for goldfish mouth rot right away.Need help on this let me know.Sincerely,Jamie BoyleThe Goldfish Guy

  12. Katie on said:

    my goldfish appear to be acting weird, they appear very healthy, but they seem to be rolling over each other and nudging each other continuously. Do you think this is likely cos they are different genders?

  13. PetGoldfishForum on said:

    Your goldfish are breeding that is exactly whats going on. Goldfish breeding starts by chasing one another and nudging. The male goldfish chases the female goldfish and nudges her until the eggs are released and then fetilized by the male. Your goldfish are opposite sex and the way to determine which is male and female is to observe and see which goldfish is the one chasing. If its chasing the other then its a male.Looks like you will be having some baby goldfish soon! Good luck as the goldfish breeding has started.Sincerely,Jamie BoyleThe Goldfish GuyNew Goldfish Forum – Join, Share photos, Stories and more – Join Today!

  14. Anonymous on said:

    I bought two beautiful goldfishs a few days ago. They are both different looking, ones ur ordinary orange looking one (Sparky) and the other is white and orange (Nimo). Sparky chases nimo around the tank, but sometimes the roles change. Nimo also chases sparky. Nimo has a bump on her tummy area, does that mean she is pregnant? Are we going to have baby nimos and sparkys? I am also concerned that they are always at the bottom of the tank and do not go at the top of the tank. They also wait for the food to sink to the bottom? Does that mean they are lazy little fishys? Plz help! Thank you

  15. cara on said:

    How old do the goldfish have to be to breed?

  16. Goldfish Newbie on said:

    hi… i've bought ranchu and pearlscale goldfih not long ago… yesterday i noticeed that thr alot tiny beads(around 50-60 of it) look that stick at the aquarium wall… im new to goldfish and dont know any abt goldfish…were these tiny beads eggs? if it were goldfish eggs,what do i do? and how to change the aquarium water during this period of times?

  17. Tawnya on said:

    So I recently had a goldfish die because my amonia levels were very high. I set up a small 10 gallon aquarium that I'll use as a sicktank for right now but in the future for fry. I have a goldfish in there and it is very bloated and he stays at the bottom. Is this swimmers bladder or is it a female ready to lay eggs?

  18. I have seven goldfish1x male fantail (gold)(breeding stars)1x female fantail (gold)1x blackmoor (female)1x Normal goldfish (gold)(breeding stars)1 x orange and white (not fantail)2 x male shabunkins (breeding stars)They are spawning and I have had 5 sets of baby fry so far. Four of these fish with the breeding stars ( fantail, normal goldy and the shabunkins). My question is why does the normal goldfish with breeding stars lay eggs? I have checked and treated for white spot but the stars are only on the gill plates and peck fins. I know that he/she laid the eggs because I separated the male fantail and the normal goldy into a breeding tank when I noticed their behaviour. I saw him/her lay the eggs and the fantail fertilize them. They are hatching 6 so far. Totally, confused please help? Lisa from Shropshire

  19. I have seven goldfish1x male fantail (gold)(breeding stars)1x female fantail (gold)1x blackmoor (female)1x Normal goldfish (gold)(breeding stars)1 x orange and white (not fantail)2 x male shabunkins (breeding stars)They are spawning and I have had 5 sets of baby fry so far. Four of these fish with the breeding stars ( fantail, normal goldy and the shabunkins). My question is why does the normal goldfish with breeding stars lay eggs? I have checked and treated for white spot but the stars are only on the gill plates and peck fins. I know that he/she laid the eggs because I separated the male fantail and the normal goldy into a breeding tank when I noticed their behaviour. I saw him/her lay the eggs and the fantail fertilize them. They are hatching 6 so far. Totally, confused please help? Lisa from Shropshire

  20. Hi Jamie, I wonder if 2 of my goldfish are dying or if they are actually laying eggs. From reading your articles, I think they are both females, both are very rounded, and being chased by a couple other long goldfish, I am worried because they look very tired and are laying at the bottom of the tank after being chased. Shall I set them apart from others? Even when they are laying down, the other fish are still poking their 'bottom'!!! What should I do?

  21. Goldfish Care on said:

    Hi Julie,It sounds to me that your goldfish are breeding. Yes the female goldfish can get very tired, injured and possibly die due to breeding. The males are relentless and will keep bumping and pushing the females around as the goldfish spawn.If your seriously worried about your goldfish you can remove the females away from the males. Just make sure that they are done breeding as if they are not the remaining eggs that should have been released from the female can pose health risks if they are not expelled.Have you seen and goldfish eggs as a result of the breeding? What you can do if you suspect they are breeding is wet your hands and remove one of the female goldfish. The stomach should be very soft. If they are truly breeding, if you gently rub the female stomach with your two thumbs and gently slide them down to the anal vent you will see if eggs are released.Just keep and eye on your goldfish and if you see severe stress among the female goldfish then I would remove them. If not it is possible they can kill them during breeding.

  22. Catherine on said:

    Hi Jamie, I've recently been trying to set up a new goldfish tank. I had four fish in the tank but one got an ulcer and three of them ended up dying. The one I had left (laura) seemed lonely so I recently bought another fish to go in with her. However, this fish seems to be bullying her. It constantly chases her around the tank and refuses to leave her alone. The newer one is slightly bigger. The older fish however, now seems to have finrot and seems very slow and miserable. I have taken her out of the tank and put her in a smaller bowl which is treated with the fish medicine Myxazin. Is this enough? What am I to do because I must be doing something wrong!!Yours, Catherine

  23. Anonymous on said:

    Hi,I have 3 small comet goldfish.I got 1:Rafiki, Four days before the other 2:Zazu and Patches. At first Rafiki went crazy and tried swimming through the glass to get away! lol. But now Rafiki is always hanging around Patches. And Zazu just stays at the bottom of the tank hiding near a log. I dont even see it come up to get food. It just waits for it to sink down and then sneakily eats. He doesnt go near the other two fish or swim around higher up in the tank. Is something wrong with it? (I say It because I don't know if they are boys or a girls!)Thanks, Nikki C:

  24. Anonymous on said:

    Hi Jamie,I meant to update you what happened long time ago. Anyway, they both got bumped around the tummy area for a few days by the male goldfish, then one day…when I got home after work, one of the two big tummy fish disappeared. The tank is covered, so there is no way that she has jumped out. So, it was eaten by other fishes!!!Then, the 2nd big tummy one got better, and started to move around more and more. But I couldn't find any eggs in the tank! They are probably eaten by other fishes as well, you think?!Julie

  25. We have had our three goldfish for about 4/5 months now and the largest one has started chasing the other smaller two. One of the small fish's tail has become bent like it is dislocated. Is there something we should do or will it right itself somehow?

  26. Anonymous on said:

    I found this fish article of great help.ThanksNadia

  27. Brandon on said:

    i have 1 black and red fish i dont no wat it is it is also little and has somethingwite on hir belly

  28. i had bought 4 gold fishes…but all the time they spend on the surface of the water…..are they r not gettin sufficient oxygen or wat??? pls help me…

  29. bgsam76 on said:

    OK so I have 2 gold fish and already went through the chasing process but also one of them does not have the fin on there back which I believe is the female as of right now she is like stuck on the bottom of the tank it looks like she is having a seizure trying to get to the top of the tank to eat at feeding time, and then falls back to the bottom and stays there she has been doing this for 2 days now. also how long will it take for the eggs to hatch and what do they look like? Help!

  30. dina on said:

    We have 3 goldfishes and yesterday one was relentlessly chasing another. It seemed like it was bullying it although it could have been the courting process! I thought that the female would not survive so i removed the male and did a water change and placed the male back into the tank (as the petstore told me to). Now the female fish is constantly at the bottom of the tank,looking very sad and upset and dont know what to do!pls help?

  31. Karen on said:

    we have one goldfish and looked after a goldfish from my sons nursery over the easter hols. i put them together whilst i cleaned tanks and kept them together for a few days as our tank is larger. our fish is now very fat and after reading about breeding goldfish i am worried now that her eggs will not be expelled and she will become ill. hope this makes sense, can u give me any suggestions please?

  32. anton on said:

    How old would you expect your fish to be mature because I have a large tank full of fan tails and single tailed gold fish and haven't seen any of the signs of breeding and I've had them for about a year. Any thoughts? Sincerely anton

  33. Anonymous on said:

    I recently bought 4 goldfish ( 1 is orange in colour n is about 6cm n the other three r 3cm n they hav orange head n white body). i dont know whether they r male or female.can u plz tel me when do goldfish lay eggs?

  34. Goldfish Care Information on said:

    Goldfish lay when they are ready. In order for goldfish to spawn or lay eggs they need to be old enough. Goldfish are generally ready to breed when they are 1 – 1 1/2 years old. You can determine the sex of goldfish by referring to my golfish article above.How old are your goldfish?Sincerely,Jamie BoyleCountry Koi Fish Farm

  35. i know this is about how they breed, but i need to know if my two goldfish are a boys or girls plz help!! i need to know

  36. how can i tell if mine white gold fish male or female.tell me plaese

  37. dorothy heltsley on said:

    We have replaced our pond liner 3 xs and something contiues to chew holes in it. We r considering a “cattle tough” type to replace it. It is made of heavy poly material. Is there anything in that material that would be toxic to the fish?

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