Home > FAQs > Stocking With Fish: Frequently Asked Questions

Stocking With Fish: Frequently Asked Questions

By: Dr Gareth Evans - Updated: 22 Feb 2021 | comments*Discuss
Fish Pond Goldfish Shubunkins Koi Tench

The idea of being able to enjoy watching a few fish darting around the open water or idling around the lilies on a warm summer’s day has a tremendous appeal and for many people, it’s almost impossible to think about a pond without its fishy inhabitants.

However, whether you’re building a new pond with fish in mind or you’ve inherited an old one from previous owners, adding fish to a garden pond does need to be thought through carefully if they’re going to do well in their new home.

What sort of fish should I choose?

What you choose largely depends on your own taste and how large your pond is – and there’s plenty to consider, including goldfish, shubunkins, koi, tench, rudd and orfe. It’s obviously important to consider the likely final size of the full-grown fish when making your choice; the orfe and koi, for instance, tend to grow too large for smaller garden ponds, though they can do very well given the right environment.

Where’s the best place to get them?

There’s no shortage of places to buy pond fish, from many pet shops, garden centres with aquatic sections and even specialist online stores that will courier your chosen fish over-night to you, in stout bags, in well oxygenated water and contained in stout polystyrene boxes.

Which of these options is the best really comes down to personal preference and what’s available, but on the whole, if you do have a good stockist, there’s not much to beat actually selecting each individual fish for yourself.

How do I know if they’re healthy?

Healthy fish look alert and comfortable in the water, and swim freely with no sign that they are having to fight against either floating to the surface or sinking to the bottom. The dorsal fin should be held upright and all of the fins should look in good condition, the eyes should appear bright and the fish shouldn’t be missing scales or have any obvious signs of damage or disease.

Keep a particular look-out for any white, furry patches that look a bit like cotton wool, which indicates that the fish is suffering from a fungal infection.

How do I know how many to buy?

The number of fish your pond can comfortably support has to do with how much oxygen there is in the water and although obviously depth, oxygenating plants, fountains and waterfalls all affect this, in general it’s the surface area of the pond which makes the most difference.

To work out how many fish you can accommodate, simply multiply the pond’s average length by its average width to calculate the surface area and then apply the general rule of 1 inch of fish per square foot – or 25cm of fish for each square metre.

It’s always better to have slightly too few fish than slightly too many – and remember that in the summer when the fish are more active, the warmer water holds less oxygen than when its colder – so it’s important to resist any temptation to over-stock.

Is there a right time of year to stock my pond?

You can add fish anytime from spring when water has begun to warm up – to at least 10 degrees C (50 degrees F) – through to the late summer.

How soon can I add fish to my new pond?

You need to allow a new pond to 'age' for a while before adding fish – so a bit of patience is required. Ideally your pond should have been planted up and the filters and other systems running for at least a fortnight – and ideally more like a month – before you introduce the fish.

Be sure to float the bags they come in for half an hour ahead of releasing them, to allow the water temperatures to match and when you do open the bags, allow some of the pond water to enter for a few minutes before you let the fish go, so they can start to acclimatise to your pond.

There are a few potential pitfalls when it comes to stocking your pond with fish, but with a bit of care and planning it shouldn’t be too hard to avoid them and the end result will be well worth the effort.

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
[Add a Comment]
I want to make a small pond in a pot but have been told i cant have a small fountain AND plants as they dont mix!Is this true?I only wanted a water lilly and whatever else is suggested?Iris & some floating cover? Any advice would be welcome!Thank you!
Jules - 22-Feb-21 @ 5:25 PM
I have stocked around 200 carp common, creation & mirror this was done last sept/Oct time the pond is large around 1/2 an acre and average depth 1M however it goes as deep as 3M I haven’t seen much of the fish and am hoping they are at the bottom of the pond, should I see them on the surface or do you think a preditor has had them ?
KDMog - 31-Mar-19 @ 7:43 AM
I have built a new larger pond and i am putting my 5 ghoast and 4 gold fish all around 12" from my old pond into the new one . Can i safly add a few more fish i am thinking koi . Would my older fish fight with the new fish
Hosta - 12-Nov-18 @ 10:24 PM
Good day, I have a pond/lake that is an acre in size with an average depth of 1-5metres, it has been established some 40 years . At present there are 17 common carp in residence average size 15 lbs, I would wish to add more variety to the pond, but although the carp breed each season there are never any survivors, regular visitors are herons and terns, but I have a feeling the carp are eating their young. If I add more fish are they going to go down the gullets of the carp? Could you please advise as to what species to add. Look forward to hearing from you.
Pearcy - 8-Sep-14 @ 9:19 AM
Hi I've got a 20m diameter pond, which i'm filteringputting through a UV filter, then out through pipes which are under pond underliner under a layer of shingle. The water is staying really clear, but i'm getting greeny/white sediment accumulating on the bottom of the pond.It seems to be generating its own gases and starting flake off and occasionally rise to the surface. My initial guess for what is was was dead algae, but it couldn't pass through the layer of underliner, so i'm rather at a loss to say what it is. Any ideas gratefully accepted
JulianS - 9-Sep-13 @ 4:12 PM
I would like to purchase book/s for planning,building and instalation of filters and electrical requirements. Do you supply? The area is approximately 36 square metres, or so.
kellie - 8-Nov-12 @ 10:32 PM
I am downsizing to a smaller pond and have a couple of koi 12"-15" long and a couple of orfe that are slightly larger.Is there any guidance as to minimum pond size for example 6ft x 3ft that the fish of this size need to be comfortable, as I wouldn't want them to go to too small a pond?
Paul - 11-Oct-11 @ 12:44 PM
I have a large garden pond (15metres square) and wish to stock it with fish. I have a problem with duckweed and have been told that the right fish could help keep this problem under control. The pond is mature and has bull rushes; water lilies and a number of marginal plants. The pond is fed from a fresh water stream and the outlet is into a river, although water flow is gentle. I live in Devon. Can you advise me on what fish to stock it with?
dyloni - 11-Jul-11 @ 5:08 PM
Jenny, It could possibly be wild mink, do you leave near a waterway, such as a canal or river?
Kev - 9-Jun-11 @ 6:20 PM
The site is very informative. I have a question that I hope can be answered. We have a large fish pond that has been established for a number of years. Over the last few days we have found a number of small headless fish floating in the pond. The pond is stocked with koi, golden rud and goldfish and it appears to be the smaller fish (approx. 2-3" long) that are being killed. We cannot understand why the whole fish isn't being eaten.we have so far lost 15 fish. We have a wlled garden so it would be difficult for otters etc to get into the garden. Any ideas?
Jenny - 29-May-11 @ 9:47 AM
Share Your Story, Join the Discussion or Seek Advice...
(never shown)
(never shown)
(never shown)
(never shown)
Enter word:
Latest Comments