Breeding
When I was growing up, you "couldn't breed Goldfish", as I've learnt more and more about the hobby, it has become apparent that this is yet another relatively common misconception with Goldfish. It's not the breeding that's tricky, let's be honest, they're like Rabbits! If you mix genders, whether you want them to or not, they will breed. It's the bit after that, that's the complex part. I think this is where the belief comes in that they're difficult to breed... Goldfish will eat their eggs and young, they're pigs. They don't raise their own. With that being said, let's take a look into breeding, from start to finish!
Raising fry isn't easy. It's not something that should be undertaken lightly. Don't breed your Goldfish on a whim, plan it. Look into the practicalities and ensure you are prepared. It is time consuming and expensive and difficult to turn a profit, but it's surely fascinating!
Selecting Stock
Goldfish have all been bred to have their specific qualities. If left to their own devices and allowed to interbreed and no culling was to take place, over a period of time they will eventually revert back to the wild form of the Prussian Carp. Selecting desirable stock (and culling undesirable fry) is vital. If you are trying to breed show quality fish, you will need to look at your selected variety’s standards. Be sure to fully research the standards for which you are aiming to achieve. The better the quality of the Goldfish, the higher the quality of the offspring. Ideally, we want to keep lines pure, so only breed Goldfish of the same variety to ensure high quality fish.
Choose your Goldfish wisely.
We want to choose healthy, disease free, active fish. Stunted fish may struggle with breeding, as can fish which have suffered severe disease/recurrent infection so I would avoid these fish.
Goldfish become sexually mature at around one year, but they can struggle to perform at first. Aim for a fish that is 2-3 years old. Young Goldfish tend to produce small yields of small eggs, and small eggs produce small fry. Older Goldfish will have higher infertility rates and there’s more risk of deformed fry.
Look at the body of the fish. If you are breeding fancy Goldfish, you are looking for a fish with a deep round body. Longer bodied fish will produce longer bodied fry. these
Now for the fins; we want fish with two anal fins of equal length. Fancy Goldfish should have two caudal fins that are fully split/divided. Select the fish with your desired fin shape. There are many different varieties, this where the research on Standards comes in. If you are breeding Butterflies or Veil Tails, the caudal fin should have little to no fork. Both Caudal lobes should be symmetrical. Missing fins are a genetic problem and these fish should be avoided.
Your chosen fish should have even sized eyes. This is particularly important if you are breeding Bubble Eyes, Celestials, Telescopes and other similar, googly eyed fish.
Genetics play a huge role in determining the colouration of the offspring. Your selected fish should be close to your desired colour. When breeding Calicos, a fish with a lot of black colouration may be bred with a fish with more white/blue tones to achieve the desired contrast. Some colours are more stable than others. Blacks, blues, bronze and chocolates are the most unstable. If the desired outcome is solid colourations (ie. Black Moors) then choose the Goldfish with the deepest colours. That being said, Genetics aren’t everything, so don’t expect carbon copies of the parents.
Look for potential. When selecting young fish to grow on to breed, select fish with good overall body shape. Juvenile Goldfish put the majority of their energy into body growth, so a young Goldfish with well developed fins is more likely to be smaller and less developed as they reach maturity. Most fin and wen development happens after body growth has slowed, if not ceased.
Of course, it is entirely up to you to choose which fish you are to breed, but remember that the genetics of the Goldfish will pass on, so aim for Goldfish with the qualities you desire. Genetic issues will become more severe as each generation breeds.
It is also quite hard to find fish which meet each criteria exactly, so be prepared to make a few sacrifices. Those dream fish are out there though, so holding off until you find the perfect match is advised.
Breeding Behaviour
Breeding behaviour in Goldfish can be very aggressive. The males will relentlessly chase the females, nudge their vent area with their faces, push them into plants and the sides of the tank, all in an effort to get her to release those eggs!
It can really take its toll on a female. I keep a colander on hand, the lips enable it to float on the surface. If my females start to look stressed and tired, they go into the colander for a little peace. The males can also damage fins and cause injuries. Breeding is normal for Goldfish, but the stress of being chased for hours can be fatal to the female, so keep an eye on her during breeding time.
Goldfish will breed when they’re good and ready. In the home aquarium, this can be year round, weekly spawnings, as they’re not exposed to the elements that would induce spawning. They will breed at some point. Remember, Goldfish aren’t picky. Males and females of all varieties will breed together, so if you wish to keep a line pure, keep the breeding stock separate from other Goldfish.
Plants or a spawning mop are ideal for collecting eggs. They’re very delicate and removing them from tank surfaces/decor can easily damage them.
Preparation & Conditioning
Preparing your Goldfish for breeding is often referred to as conditioning. There's a few things you can do to get your fish ready to breed. If that the Goldfish you have selected for breeding have been given the best possible care, pristine water and lots of room for the last couple of years the likelihood of successful spawning is much higher.
Goldfish naturally breed in the spring time, when there is an increase in the water temperature. Increasing the tank temperature a few degrees (from 14-16c to 18-22c) will trigger the females to produce eggs. It’s advised that the tank temperature be on the cooler side for a few months, to give the fish a winter period. Fertility rates are higher where the fish has had a hibernation period.
Ideally, conditioning would start in the autumn, particularly if you are breeding in a pond environment. Ensure your Goldfish go into the winter in the best condition possible. In the winter, Goldfish live off fat supplies, these fat supplies are used to encourage the female to produce eggs. In an aquarium environment, this is achieved by adding lots of protein/live foods to the diet of your Goldfish. Once the fish have had their hibernation period, where they have been fed sparingly, if at all, due to the decrease in metabolism, you can start to increase the protein/live food content of their diet.
Daily water changes of at least 25% should be performed (alongside the weekly 50+%), this will help to improve the overall health and well being of the fish.
The spring time also means that days are getting longer, so during the hibernation, reduce the photoperiod in the tank.
Preparing the Fry tank
You will need a tank that contains 30+litres. Choose a tank or tub that has maximum surface area and fill with fresh, aged water.This water should be no more than 6" deep. This ensures the weight of the water doesn't damage the fry, and aids them in reaching the surface.
A sponge filter is ideal filtration for a fry tank as the low current doesn't push them around too much, doesn't draw them into the intake and creates plants of surface agitation.
Get yourself a heater and heat the fry tank to the same temperature as the breeding tank..
