Article and photographs by Bob Jones, BAS

The information in this article is ordered by topics (conditioning, breeding, etc.); please see the Goldfish Breeder's Diary for a sister-article with the information ordered by the time of year in which the activity takes place.

For another, very similar view of the goldfish breeding process, please see our original article by Bill Ramsden.

Conditioning the fish during the autumn prior to breeding

The whole process begins in late summer, in readiness for the following breeding season. All the fish in the fish house are put outside in clean ponds some time in November, although by now most of my adults will already be outside. From then on, I make sure they are well fed with good quality dry foods and daphnia. While the water temperature remains above 15°C (60°F), I will feed Hikari Gold pellets, which contain 42% protein. When the temperature drops between 10–15°C (50–60°F), I feed Hikari Staple pellets at 35% protein. Finally, below 10°C, I feed Hikari Wheat-Germ pellets with 32% protein. Then, when the water temperature dips below 7°C (45°F), I stop feeding altogether. During this period I also give them as much daphnia as I can, and I make sure the water is in tip-top condition. At the lower temperatures, I feed them in the early afternoon which is when the water temperature is at its highest during the day.

When I stop feeding altogether, I will not resume feeding again, even if we have a mild spell. I like to let the fish have a complete rest for a couple of months or so; I think they spawn all the better for having this dormant period.

Preparing the breeding tanks

With the fish house empty, I will now deep clean all the tanks and leave them bone dry, along with the nets, hoses, heaters and air stones etc. This is to kill off any parasites etc. The fish house troughs will also be cleaned, but after cleaning I‘ll refill them with water; this is because they were built using concrete blocks; consequently, if they were left to dry out, the walls would probably shrink back and crack. When all this is done, I also carry out any fish house maintenance that needs doing. Most years there is always something that needs attention; I’ve always found that if you leave it, it never gets done. Apart from keeping a close eye on the fish, and the quality of the water, that’s about it for a month or so. Well at least until the really cold weather arrives.

Overwintering the fish

When the water temperature falls to around 3°C (37°F), I’ll bring some of my fish into the fish house to protect them from the worst of the weather. My Bristol shubunkins and fantails will stay outside all through the winter, no matter how cold it becomes, but my calico veiltails and moors will be brought inside and placed in tanks with a 50 watt heater. I try and keep the water temperature in these tanks between 4–8°C (39-46°F), and, although my fish strains are fairly hardy, if these two varieties are left outside they will suffer, and it will take much longer to get them to breed in the spring.

Bringing in the fish in springtime

It takes me between 4–6 weeks to condition the fish ready for spawning, so, if I want spawnings at the beginning of April, I’ll bring them into the fish house some time during the middle of February. I always condition the fish in the tanks on the right-hand side of the fish house, and spawn them in the tanks on the left; that way they go into clean tanks when they breed. I fill all the tanks on the right-hand side with water from the ponds where the breeders have spent the winter; an air stone and 300 watt heater (turned off) will be placed in each tank.

The next day (making sure the water temperature is the same), I’ll bring the shubunkins and fantails in, and they will join the veiltails and moors that are already in the fish house. I separate the sexes and keep the males in the top tanks and the females in the bottom ones; I give the males the best tanks as I believe it’s slightly harder to condition the males than the females.

Conditioning the fish for breeding

It is now that I will treat the fish against flukes etc. I always use Fluke-Solve which contains praziquantel; the recommended treatment is 1 gram of powder to 55 gallons. I consider Fluke-Solve to be the best anti-parasite treatment around, as it’s very gentle on the fish, quite unlike some of the treatments that are available, like formalin or potassium.

I now start to slowly raise the water temperature until it reaches 18°C (65°F); this will take around 10 to 14 days. I do this by using plug-in timer switches; the heater comes on for longer periods of time as the days go by. The first day, I’ll set the timer to come on for 15 minutes every 2 hours, and then slowly increase the time every day.

Also, after 2 days, I’ll turn on the water drip system and start feeding: I start off by feeding pre-soaked Wheat-Germ pellets and daphnia (I can just about obtain enough from my daphnia ponds at this time of year); as the temperature increases, they go on to pre-soaked Hikari Staple pellets, flake food and daphnia; finally, when the water temperature reaches 15°C (60°F), I’ll feed pre-soaked Hikari Gold pellets, Dendrobaena worms and daphnia.

I syphon the tank bottoms every day, and the drip system will change a quarter of the water each day. It’s very important that the water conditions are kept as good as possible with all the heavy feeding.

During or towards the end of this 4–6 week period, the males will now be showing breeding tubercles on their gill covers and pectoral fins. The females will have swollen abdomens, which, when pressed lightly, will feel very soft to the touch. The fish are now ready to spawn, but, before moving them to the left-hand side of the fish house and putting them together, I will turn off the running water and treat them once again with Fluke-Solve. This will make doubly sure they are free from flukes etc.

By now, my fish are fully conditioned and ready to spawn. All the fish are bright and alert and are being kept in water temperatures of around 18°C (65°F). I now re-treat the fish against flukes etc. using Fluke-Solve; they will stay in this solution for 48 hours. Feeding will be maintained but at a much-reduced level.

Setting up the breeding tanks

At this time I will set the breeding tanks up. I use the tanks on the left-hand side of my fish house, which are south-facing. These tanks have been empty and dry for several months, so there is no risk of disease being present. I fill them with tap water and treat it to neutralize the chlorine. An air stone will be placed in the water and left to bubble for at least 24 hours. Just before the fish go in, a heaterstat will raise the water temperature to 18°C (65°F), then the spawning mops will go in. The mops I use have been made from unravelled Shower Body Puffs: they are cut into thin strips about 45 cm (18 in) long, 30 or so bundled together and weighted down in the middle with some lead; the free ends will float up and will behave just like a plant would. This year (March 2016), I’m making some mops out of green acrylic wool, so I’ll have to see how that works out.

Selecting the breeding fish

By now, I have already decided which fish to use; this is how I do it. It’s generally not recommended to do a sibling cross (brother to sister), but sometimes, for various reasons, you have to; just don’t make a habit of it. I’ve occasionally done it and had fairly good results, but I certainly don’t do it as a rule. I normally cross young males with their mother or grandmother. I rarely outcross as I’ve found this can set your strains back; I only do it if I absolutely need to, for instance if any of my strains loses vigour or if I see a fish with a prominent feature that needs to be improved in my own strains. I’ve bred my metallic fantails now for over 25 years and I have never outcrossed.

Sometimes I have a fish that I know will throw good offspring, so I’ll use that one, but as a rule this is what I look for: I’ll look at my fish in general and decide what is the one feature that most needs improving; let’s say the dorsal fins are a little on the weak side, I will then select males and a female with strong, erect dorsal fins; this will improve this feature in the offspring. Now of course, all the other characteristics need to be as good as possible also, or over time your strain will slowly deteriorate. It can be a bit of a juggling act but you must do the best you can. In metallic fish I’ll choose the fish with the deepest colours, and in calico fish I tend to breed a red(ish) fish with a blue(ish) fish; I tend not to use two fish with similar colours as this always seems to leave the offspring lacking in colour. Also, it’s always best to use fish with vigour, particularly the males, or over time the strain will weaken.

Spawning the fish

The breeding tanks are now ready for the fish, the water has already been treated, and the temperature is now 18°C. A heaterstat and spawning mops have been placed in the tanks; now is the time for the fish.

I use one (maybe two) females and three males. I normally put them together in the morning and keep my eye on them for the rest of the day. I don’t feed them on this day. During the day, or maybe that evening, they should begin to chase, albeit in a half-hearted manner. If I’m lucky, they might spawn early the following day. If they don’t, I will resume feeding, but only the bare minimum. I like to keep my fish on the hungry side during this period, as it keeps them more alert and active.

They will normally spawn well within five days and I always try and keep the water as healthy as I can. I syphon the tank bottoms every day and keep the front glass clean. Because I usually set up six or seven tanks at the same time, I always find that once the fish in one tank spawn they all seem to. When the female is ready to spawn, she will release pheromones into the water to excite the males; strange, but it almost seems these pheromones are transmitted through the air and this gets all the other fish excited as well.

I always let the fish spawn naturally for a while, but when they are 60% through it, I’ll then hand-strip them (that’s if I’m around). This way I get the best of both methods and I normally obtain pretty good hatch rates. When I hand-strip, I do it in a white washing-up bowl ¾ full of water. I milk the males first and swish the water around. Then I do the same with the female, holding her under the water with her vent just under the surface; when the eggs are being released, I move her around the top of the bowl, thus spreading the eggs to ensure they’re well spread out and not clumped together. When I’ve finished, I let the bowl sit for five minutes and then pour the water away, and I then vigorously swill the eggs with water from the tank. I do this two or three times, as this washes any dead milt etc. away from the eggs.

Hatching the eggs

When spawning is over, the brood fish are moved to a separate tank, as, if not, they will eat the eggs. The bowl containing the fertilized eggs is then placed in the tank in an upright position with an air stone in front of it, bubbling away; this keeps the eggs well oxygenated. The heaterstat is then set to 21°C (70°F). I then carefully syphon the tank bottoms; the eggs won’t be syphoned away as they will have stuck to all of the surfaces. I then clean the front glass but not the other parts of the tank; I leave these green as this will supply some food for the newly hatched fry.

Just before the eggs hatch the air must be turned off. The eggs will hatch in four days, or three days if the sun raises the water temperature during the day. I try to keep the temperature below 25°C (77°F) by changing some of the water if necessary. When the alevins break out of their eggs they will hang onto any vertical surface by means of little sticky pads; they will hang there for two days as they absorb their yolk sacs. In addition, when they break free of the eggs, I will soak and mush up a couple of Hikari Gold pellets; I squeeze this through a fine mesh handkerchief into the water so it forms a cloud (many breeders just use Liquifry); this will encourage the production of infusoria which the fry will live on when they become free swimming. After the two days, when the yoke sac is consumed, the alevins will struggle to the water surface and take a gulp of air; this will fill their little swim bladders and off they’ll go.

Feeding and raising the fry

Let me say this. From this point on you must ensure the tank never becomes polluted. Remember the old adage, you don’t keep fish, you keep water. It’s a really fine line between feeding heavily and overfeeding. The latter will produce weak, slow-growing, diseased fish – that’s if they survive at all. Feed heavily if you must but be very, very careful. I have a ‘running water system’, whereby the water trickles in one end of the tank and exits via an overflow pipe the other end. The standpipe is covered with filter foam so the fry are not washed away. The trickle is set up to change 50% of the water every day; as I use aged water (no chlorine), I don’t have to treat it.

The moment the fry become free swimming, they will feed on microorganisms within the tank, much of which will consist of infusoria and algae etc. At this time I will once again squeeze in several small clouds of Hikari Gold mush (or Liquifry) around the tank for them to feed on. The fish will continue to become free swimming during the day.

First thing on the second day, I will start feeding them on brine shrimp. I will have already set the hatchery up 24 hours prior to this. I feed them four times a day; that’s roughly every four hours, and I make sure there is shrimp swimming around all the time. Any dead shrimp is syphoned out every day using some airline. It’s universally accepted that brine shrimp is the best food you can give them, that’s if you want them to grow reasonably fast.

I continue to feed brine shrimp until the fry are big enough to take very fine daphnia, which is normally around 10–14 days. I’m very fortunate to have my own duck pond which measures 35 x 12 feet (10.7 x 3.7 m); this supplies me with more than enough daphnia for my needs. I grade the daphnia by using different-sized sieves; the first sieve I use is a very fine tea strainer. I always try to ensure there is daphnia in the tanks most of the day, although I’m careful not to put too much in at any one time, as they will compete with the fry for oxygen. But, as I have running water and an air stone gently bubbling away, this is rarely a problem.

After a couple of days, or when the fry have become used to the daphnia, I’ll also start feeding dry food. I always use Hikari Gold, but any good quality high-protein food will suffice. The fry won’t take to this new food straight away, but after a few days they should start taking it. I always syphon out any uneaten food after a couple of hours, as any high-protein food will pollute the tank in double-quick time. I never leave uneaten food in the tank overnight.

Just as I do with the daphnia, I grade the dry food; I grind the pellets in a coffee mill and sieve it through different sized sieves. The finest sieve will only let dust through and this is the first food the fry receive. As the fry grow bigger, so does the food.

Fry need four things to grow quickly: good water, good food, heat, and space. I always try to maintain the water temperature between 21–26°C (70–80°F). If it’s a hot sunny day, the temperature might exceed this; luckily, my running water helps to keep the temperature down. As the fry grow, I try to give them lots of space. I do this by either spreading them out in spare tanks or by culling, whenever it becomes necessary.


For a detailed description of the culling process, see the Goldfish Breeder's Diary for May, June, July and August.


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