If you’re a fish-fan, then sooner or later the prospect of breeding your own is almost certainly going to appeal – always assuming your fish haven’t already beaten you to it, and started producing ‘tiddlers’ all by themselves!
There’s nothing particularly difficult about breeding fish in your own back garden – at least not in principle – and left to their own devices, generations of goldfish have been simply getting on with the business of reproduction without the need for any assistance from us. Never-the-less, if you are set on helping nature on its way, here are a few simple ways to increase the chances of getting started producing your own, home-grown fish.
First, take a look at your pond. Good water quality and adequate aeration are essential prerequisites, so if it’s heading towards summer and you haven’t tested your water in a while, now’s a good time to check everything is well before the breeding season gets under way. Make sure your filter system’s working properly too, changing the UV bulb if necessary; goldfish don’t need clear water to breed, but you’ll doubtless want to be able to keep an eye on what’s going on!
Good planting within the pond is another important consideration, both to provide the fish with a good spawning site where their eggs can stick to the submerged leaves and as a protected nursery for the fry that ultimately emerge. Unfortunately many fish have cannibalistic tendencies and will happily eat their own eggs and offspring, so having an area of relative safety where the youngsters can hide out and grow is a crucial part of the proceedings.
The Fish Themselves
Obviously you need both males and females, so check to see that you do; although not all kinds of fish are the same, as a general rule, males tend to be more streamlined, with larger and more showy fins, while females appear rounder and more sedate in the fin department. It’s usually easy to get the hang of this with a bit of practice, but if you’re still not convinced, it’s probably worth asking a knowledgeable fellow-keeper to make sure you’re on the right track.
Some fish breeders suggest that the males should outnumber the females, while others point to the physical exhaustion caused by having females permanently pestered by amorous suitors – especially with koi. On balance, a slight male-bias is probably advisable, but do keep a watch to make sure that things don’t get too rough; highly stressed, worn-out females hardly make for the most successful spawning!
Equally obviously, they also have to be sexually mature. This is another thing which varies with species; for goldfish, for instance, this means over two years old, while koi aren’t ready to breed until they are at least twice that age.
If you’ve got all these prerequisites right, the males have, with varying degrees of aggression, chased the females around for a while, and they have in turn responded by shedding their eggs for fertilisation, all that remains is for the eager fish-breeder to wait for them to hatch. Fortunately you don’t have to wait long; although it is temperature dependent, as a general rule for example, goldfish fry appear within two or three days – although they take about as long again to begin to look like proper fish, and as much as a year to develop their final colour. Many a novice breeder has wondered why there are no young goldfish and what kind of fish has produced all those brown babies!
Their nursery area will provide plenty of useful natural food for the young, but it is important to provide a good quality, specialist fry food to ensure they get all the minerals, vitamins and nutrients they need to keep them healthy at this stage of their lives. Growth is usually quite rapid in the early days and weeks in most species of pond fish – it’s nature’s way of helping them to avoid falling foul of all those hungry mouths that share the pond with them!
Unfortunately it doesn’t always work and the harsh reality is that the odds of survival for any one individual are very poor, but the good news is that with so many eggs being produced, there’s a very good chance that at least some will make it to adulthood and breed themselves. It is, after all, a cycle that has been playing out for millennia – and one which can, with very little effort, allow you to enjoy the simple pleasure of fish breeding for yourself.