How to Add Goldfish to a Pond

When you have finally reached the stage where you are ready to add goldfish to your pond, it can be very tempting to rush out and buy a large selection of fish immediately!

However, it’s important to handle the introduction of your goldfish slowly to avoid placing too much of a strain on the natural ecosystem of the pond, and allow the pond to mature and acclimatise.

If many fish are added all at once, the filter does not have time to adjust to the new bioload and an “ammonia spike” will be caused due to a sudden influx of waste, an ammonia spike like that will cause your pond to “crash” killing everything in it.

Introducing your first fish to a pond

Start off with just one or two goldfish for your pond, and introduce them to the water gently.

When you get your goldfish home from the pet shop, aquarium or garden centre that supplied them, it’s important to make sure that the water temperature and quality between your pond and the water they have travelled in are equalised gradually.

Begin by floating the closed bag that your fish travelled in on the edge of the pond, to allow the water temperature in the bag to adjust.

Gradually, add pond water into the bag over the course of an hour or so to allow your fish to get used to the difference between the pond water and the water they came from.

Can I put the water from the bag in my fish pond?

  1. Firstly, NEVER ever put the water from the bag into your pond, as this can be very damaging. This is because many fish stores move on so many fish that the nitrates are very high, so the water they come in will have poor quality.

  1. Secondly, with that movement of fish, many diseases and pathogens can be in the water which you would then be adding to your pond.

  1. Thirdly, fish stores use trace amounts of copper to combat parasites like white spot and fungus, copper is highly dangerous in a small environment, it is lethal to fish longterm and outright kills bacteria and invertebrates, so never add water from the fish store to your pond or aquarium.

When the temperature in the water and the bag have equalised and your fish has had time to get used to the change slowly, use your net to remove the fish from the bag and place them in your pond.

Dispose of the water from the bag away from your pond.

After adding your first lot of fish, give them a couple of days to settle. Observe them closely for any signs of weakness or disease – if they are healthy and doing well, go back to the same store to pick up more, if they are not and need treatment, do not buy anymore fish until they are cured.

Adding additional fish to a pond

Be careful when buying new fish; everytime you add fish, you are adding new pathogens and setting the rest of your animals at risk. 

Ideally, quarantining your fish is the best plan of action if you have a spare tank, large bucket or pond, to allow them time to fend off any disease before you add it to the rest of your fish.

If not, be picky about the fish you choose. Health check the fish or ask a member of staff at the store to do it for you, (but always double check).

You should:

  • Look for white spots in the tanks;
  • Ask them if they treat whitespot with copper;
  • Ask them how long they have had the fish in for.

If the store has only had the fish for a day or so, do not buy them. Wait a few days for the store to hold onto them – this way, they will be properly treated for disease, have settled down a bit and have eaten and will then be ideal candidates for you to take home and add to your pond.

The do’s and don’t of adding goldfish to a pond

There are a few tricks to adding fish to a pond which can make life easier, there are also some key things you should avoid if possible that would put your fish and pond at risk.

Things you should do:

Acclimate your fish properly.

As mentioned before, proper acclimation is key. Float the bags to get them to the correct temperature, and then add some of your pond water to the bag gradually to get them used to the new water conditions.

If the change in temperature and water chemistry are vast, take longer time to acclimate. Leave the fish for 30 minutes to an hour in the bags before adding them.

Once the new fish are added, leave them alone.

Moving is extremely stressful for fish, and you staring at them is adding to that stress.

High stress for long periods of time lowers the immune system of your goldfish and they become ill – this is usually what happens when fish undergo a stressful move, so it is important that you minimise stress as much as you can.

Quarantine your fish if you can.

Adding new fish to an already established pond is the number one cause of disease outbreaks. As pathogens are brought in on new fish, even if they are not infected themselves, they still carry the pathogens on them when they enter your pond.

Things you should not do:

Rush the acclimation process, especially for large goldfish.

Moving large goldfish can be very difficult, as their bodies adapt much slower than younger and smaller fish, especially when they are used to living in certain conditions.

If possible, try to avoid moving larger specimens too much, and if you must, allow them extra time to settle and acclimate.

Move goldfish and carp outside during winter.

Taking goldfish from an indoor aquarium or pond and moving them outside is a big change for fish. Doing this during the winter months is unwise, as sometimes the cold is too shocking for them, and they can die.

To avoid shocking fish in winter, other measures can be taken such as heating the pond, although this is very difficult to do or covering up the pond. Although possible, the risk of death or sickness is high, the change is highly stressful and can be costly if you choose to heat the pond.

In any case, we always recommend against moving fish out during winter, wait until spring when the weather is much warmer and the pond rises above 7C 44F.

Add water from fish stores.

As mentioned earlier, adding water from a fish store to your pond is not a good idea and should be avoided.

Add too many fish at once.

This can shock your pond’s bacterial bioload capacity and cause an ammonia spike, which can kill your fish. Introduce your fish gradually, so that your pond can get used to the goldfishes’ waste amount.

1 thought on “How to Add Goldfish to a Pond”

  1. my pond is 4 ft. sq. and 3ft. 6ins. deep i have 4 small goldfish already.can i add a few more. at least six more.


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