How to Breed Goldfish Like a Pro in 7 Steps
Are you ready for the next level of goldfish keeping? Breeding could be the pastime for you. Whatever the reason, you’re in the right place today!
Now, I’ll admit it: Sometimes, it’s not as easy as you’d think. But there are some “master secrets” I’m going to share here that should REALLY help you on your way to your first spawn.
Are you intrigued yet? Keep on reading!
Tips for Breeding Goldfish Successfully
Now before we dive in, just know there is no one right, perfect formula for how to breed goldfish. There are many methods and what works well for one doesn’t always work for another. I’m showing you the best of what I know from my own experience and have learned from other amazing goldfish breeders. (And I’m sure there are others who know more than I do!)
But there does seem to be a general pattern that follows the cycle of the seasonal conditions in nature as the weather goes from winter to spring, which is breeding season for goldfish. The best part? You can mimic this natural cycle in an indoor tank – you don’t have to have a pond for this to work.
Also: Your fish must be 100% healthy for this to work. Goldfish almost NEVER breed in anything less than perfect conditions, physically and in their environment.
If you are interested in breeding goldfish, but you’re unsure of exactly where to start, check out our book on Amazon, The Truth About Goldfish, which breaks down everything from breeding and raising fish to increasing your tank size to accommodate a bigger family.
If you’re struggling with health issues in your fish… you might not be ready to embark on this journey. Okay, now that all the fine print’s out of the way, here’s the good stuff.
- Males and females need to be housed together during conditioning to influence each other through hormones. If you must house them separately, the water should be shared as much as possible between the tanks. A tank divider would be ideal.
- The fish should be sexually mature, which is typically at least 8 months old, but preferably over a year or more.
- Only 1 male and 1 female are required to spawn but success tends to be better with a 2 to 1 male to female ratio and more fish. More females can encourage other females to drop eggs.
- Don’t use charcoal in your filter. Charcoal can absorb the pheromones goldfish produce needed to trigger breeding.
The 7 Steps to Breed Your Goldfish:
1. Winter Cool-down
(This is the prelude to breeding season in some areas in the wild.)
A period of cooler temperatures will help the fish think it’s in winter, which will in turn make the shift in warm temperatures more likely to trigger spawning behavior. This can be anywhere from 40-60 degrees F. (Note that most fancier goldfish don’t do as well at the lower end of the temp range.)
To do this, you can put your goldfish in a cool place in the winter, such as an unheated basement or garage. They’re best kept around 55 F. During this time, you can feed less/not at all and do less frequent/no water changes to help replicate that period of winter dormancy.
Just keep up the aeration.
They can remain in this state for anywhere from 4 weeks to several months, depending on your schedule. But 4-6 weeks is generally recommended.
Now: What if you live in an area that doesn’t get cold winters? Don’t panic: There are MANY factors to consider when it comes to spawning, and not all of them have to be there perfectly each time. You can still induce breeding by mimicking other winter-type conditions.
Remember: Goldfish are largely produced in areas like Thailand – places that don’t get cold winters either. And goldfish are an invasive species. They are quite adaptable to different conditions.
So to work around a cold dormancy period, you can keep the lights off, withhold food and water changes for 4-6 weeks. Once you resume the water changes, light and food, the fish will often spawn after the first storm.
The takeaway? Goldfish can even breed without undergoing a hibernation period… but it does seem to make things easier.
2. Spring Warm-up
The ideal temp for spawning is anywhere from 68-75F (with 70 being the most ideal), but warmer than this can work as well if you live in a hot place. But if the water was cooler first, you need to raise it gradually or you can shock your fish.
No more than 3 degrees per day is recommended at a time. You can do this with a good aquarium heater (and use a thermometer just to double-check). Some get fancy and use a timer since you can just set it and forget it.
3. Longer Light
As winter ends and spring comes, in the wild the days get longer, with more and more light. This helps the fish with hormone production needed to induce breeding behavior. 12+ hours a day of light is recommended. Some even go up to 18!
After the first spawning, you can cut it back to 8 hours for 2 weeks and then gear up to 12+ again to get them started. Goldfish can spawn multiple times throughout the spawning season. Setting the lights on a timer can really help with this.
4. Conditioning the Fish
If you want to know how to breed goldfish, I’ve got an important secret for you: Conditioning.
See, fish need extra food to really crank out eggs and milt. So you can feed lots of high-protein live or frozen foods (in addition to normal feeding of a high quality staple diet).
- Live earthworms
- Frozen bloodworms
- Frozen brine shrimp
They will get heavy and plump and will be spawning in 10 days to 3 weeks of these!
You can feed as much as the fish can eat in 15-30 min at a time 3-4 times daily (total food) – but keep the water clean. Pumping the protein is what helps the female goldfish develop eggs.
Towards the end of the conditioning period, the female will become “ripe.” She’ll start to look heavy and jello-y in her abdomen while she swims. Her stomach will become soft as well. That’s because she’s filling up with eggs! Males will get breeding stars on their front fins and gill plates. They’ll also start producing milt inside their bodies.
Now, focusing on the bloodworms/earthworms from the start and then switching to brine shrimp at the very end seems to be an often effective strategy to trigger spawning.
Oh, and don’t forget: GRADUALLY increase the food. Goldfish don’t take well to major changes. Again, this is not a normal diet schedule recommended for goldfish, just for breeding purposes. Long-term use on this fattening regimen could cause health issues.
5. Water change increase
How much? 15% three times a week is mandatory with the heavier feeding. Some find they need to do 20% daily to keep the water in order. (Yes, breeding goldfish is a lot of work!)
When you really want the fish to spawn, you can amp it up it to 50-90% daily for a few days after a low pressure storm or shortly before the full moon. You can do water changes with cooler water, which helps promote spawning as it warms up.
For these big water changes, use water that’s 3-5 degrees cooler than the tank water. All the fresh, cool water helps mimic spring rains. Doing these in conjunction with the heavy feeding really steps things up.
If the fish don’t spawn at this point? Repeat this process until they do!
6. Add Your Spawning Mops
Spawning media like spawning mops or live plants shouldn’t just be thrown in last minute to catch the eggs. Why? Having a place to lay the eggs is a factor goldfish consider when deciding to breed or not (source, page 8)!
If your fish are spawning in a tank, you will DEFINITELY want to throw in some material for them to spawn on – but otherwise, add the spawning media as soon as you begin conditioning.
Some theorize that the fish feeling the spawning media tickling on their stomachs as they swim helps them think about breeding.
If you want to go natural:
Use real live plants.
And lots of them. Hornwort is a fantastic plant for this. Goldfish don’t eat it in my experience, and it grows so fast you can replace it when needed.
Cabomba (aka Fanwort) can also be perfect as it is much softer on the roughhousing fish and has lots of lush hiding places for the eggs to land. (I think I love this one even more than hornwort and use it in my own breeding tank.)
Also: You can use artificial spawning mops handmade from green nylon yarn (not wool; it will rot) or even green cheerleading pom poms, idea credit to goldfish breeder Gary Hater. They’re reusable (can be cleaned with bleach) and soft.
When the fish are breeding, the males will push the females into your spawning media where she will be temporarily stuck, allowing them to push out the eggs and fertilize them.
7. Strategies for Non-Spawning Fish
For whatever reason, sometimes goldfish can really be reluctant to spawn. If you’ve tried the above method and it just isn’t working, here are a few things you can try.
One tip for breeding goldfish who are reluctant to spawn is to use a tank divider to separate the males from the females for a few weeks. They can smell each other and sense the pheromones in the water… But they can’t access each other.
This seems to be especially useful for line-bred fish. (It builds anticipation.) Then you can remove the divider when you want them to try to spawn again. If this doesn’t work, you can use 2 different tanks to separate them for a week and try again. You can also share the same water with water changes to spread the pheromones around.
If you skipped the dormancy step with cold weather, now could be a good time to try it. Yes, it might set your plans back, but it can work.
Some female fish have issues with infertility or lack of the hormones needed to trigger males for various reasons. Large breeding operations sometimes inject a drug called Ovaprim into the fish to induce ovulation… But this isn’t usually recommended for the average hobbyist.
There’s a big risk of harming or killing the fish if you aren’t very experienced. Instead, you can try adding chasteberry powder (aka Vitex) or red raspberry leaf powder into the food for the female during the conditioning weeks (I like to use gel food for this).
A recent study has shown that chasteberry can help induce ovulation in women struggling to conceive. Red raspberry leaf supplementation has also been used in cats and dogs to assist in inducing mating.
They can work by helping to regulate hormones to do what they’re supposed to do at the right time. So, I open up a capsule and sprinkle a small pinch of the contents onto the gel food I’m going to feed (don’t give it to the males).
In my opinion, it’s worth a try! That said: Sometimes fish are just barren – meaning they have no eggs at all. If that’s the case no amount of hormone injection or supplementation will work.
If your fish still aren’t spawning after all this, ask the following questions:
- Are you SURE you have both males and females?
- Are your fish old enough to breed?
- Were there any preexisting diseases or health issues that could impair spawning?
- Is there poor water quality or disease-preventing spawning?
Goldfish Behavior: Chasing Each Other
Usually, this means the fish are trying to mate. Goldfish aren’t normally aggressive unless they are living in cramped conditions. Chasing is a classic sign of spawning in goldfish. Females are chased, males are the chasers.
Sometimes multiple males will pursue the female around the tank like they are trying to kill her, but in reality, they are trying to push the eggs out (so they can be fertilized)! They might also tug at the fins, causing tears. Yes, this is stressful.
If things get too out of hand and the female is totally exhausted and looking poorly, it’s probably time to intervene. Otherwise, you can throw in some spawning mops or plants and collect the eggs later if you are interested in raising fry. Lastly… Male goldfish may chase each other around in the absence of females.
- Related Post: How to Raise Baby Goldfish
How do Goldfish Mate?
There are two ways: The natural way, and the mechanical way.
This first way is done in 5 steps:
- Female and male goldfish enter a period of warmth and abundance, usually a transition from colder weather and less food.
- The female goldfish begins developing eggs inside her body, while the male goldfish develops breeding stars on the gill plates and leading rays of the front fins. The male goldfish also develops milt in response to pheromones produced by the female goldfish.
- When the female goldfish is ready, she begins releasing pheromones into the water to trigger spawning.
- Male goldfish chase the female, nudging her abdomen with their noses. They may also bite or nip at the ends of the fins. The nudging releases the eggs into the water, where the male fertilizes them with his milt.
- The sticky eggs then land on surfaces below the fish, where they will either hatch (if fertilized) or be eaten by the parents.
Here is how the mechanical method is done:
Hand Spawning Goldfish
Once your goldfish are in breeding mode, there are some benefits to hand spawning them.
- You can easily tell the males from the females.
- You can also get a higher hatch rate by hand spawning the fish.
- The fish can be quickly removed so the eggs don’t get eaten
But WAIT! Before you try this at home: This is not recommended for beginners as it can permanently hurt or kill the fish, and there is risk even if done properly.
Natural spawning is the safest for the fish, though it can be stressful. How do you know if they are in breeding mode? The female’s abdomen should be nice and soft. The male should have breeding stars. You will see chasing if the fish are together. Hand spawning is nice because you control who the parents are.
Here’s a great tutorial by expert goldfish breeder Gary Hater:
It should never be attempted if the fish aren’t already chasing though. Goldfish aren’t like cows – you can’t just milk them when you feel like it. The fish must call the shots. Again, you should NEVER try this until your fish are actively chasing and/or spawning already on their own.
- Related Post: How to Hatch Goldfish Eggs
Why Breed Your Goldfish?
I hate to break it to you, but if you want to know how to breed goldfish because you have dreams of making big money selling your fry while doing what you love you can probably forget about that right now.
Not unless you can do it on a large scale and sell to distributors with good connections. The reason? It’s a TON of work (all those hours required add up). And it usually takes more money to do it than you’ll even make!
On top of that: The overhead is high in smaller scale setups. You have to pay for food for the babies, the water bills, spare tanks, electricity – the list goes on. So: Why do you want to do this, if it’s not for the profit? It’s a lot of work, after all.
But there are reasons you might do this. Maybe…
- You just want the thrilling joy of rearing your own baby goldfish by hand, seeing them grow and develop.
- You have some drop-dead gorgeous parents-to-be on hand.
- You want to continue the linage of your beloved pets so it’s like keeping a part of who they are after they pass on.
- You love the goldfish hobby and want to have a ton of them, or a few very nice ones.
- Or maybe you want to have a never-ending supply of healthy fish and never want to have to quarantine new fish again.
No matter the reason, breeding goldfish can be an educational and fun experience.
Now you know how to breed goldfish. Have you ever tried this? Have any tips to share?
See Also: How to Raise Aquarium Fish for Profit