Maintaining good water quality in your fish pond

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Keep Fish Pond Water Clean, Clear and Healthy

Clean, clear and and healthy water is the make or break for a successful and aesthetic fish pond. Read on to find out how we do this, and how you can ensure crystal clear water and happy fish!

Setting expectations for a successful pond

First and foremost, it must be said that fish ponds are not sterile environments like a swimming pool. Therefore we cannot expect them to look like one. Ponds are full of life! We aim to increase this natural biodiversity in order to maintain a healthy ecosystem balance. Algae Bactera, insect larvae, worms, tadpoles, frogs, fish, and crustaceans are all part of the mix. We shouldn’t be too alarmed if we see some algae in the pond as this is also part of the natural ecosystem.

As much as we try to emulate the natural environment garden fish ponds are generally put under different pressures than the ones we see in nature. Firstly, we tend to stock our ponds with hundreds of times more fish (in terms of weight to volume) that we could find naturally. We then have to feed all of these fish and deal with the waste they produce, all while expecting our water quality to be like that of a swimming pool.

This is why we need appropriately sized biological pond filters to help us remove all of the waste produced by the fish and process the nutrients that would otherwise accumulate in the water over time, making our fish sick and our water quality diminish. You can learn more about biological filtration HERE

How many fish is too many?

It is very important not to put too many fish in your pond. Too many fish create an overload of waste, leading to many water quality issues down the track.

As a rule we like to have a maximum of 4 – 5 koi per 1000 litres of water. Not exceeding this number of large fish will help ensure that your water will stay good and, in the event of a power outage or pump failure, your fish are far less likley to suffer from lack of oxygen in the water.

Less fish obviously means less food, so your filtration system will be able to deal witht eh fish waste more effectively. We like to feed out fish whatever they will totally consume in a minute or two.

Even in ponds that are not overstocked, with proper filtration and feeding, we can still experience water quality issues. Differing levels of sunlight, temperature swings, plant cover, stocking, feeding, filtration, volume, depth, etc all impacts your water quality.

When we try to improve the quality of the water, it is important to try to get to the root cause of the problem and treat that, rather than just the symptoms.

Although the causes of poor water quality can be blamed on many factors, the symptoms often present in one or more of the following ways:

Brown Muddy Water

This can indicate that your fish are digging into water plants/pond sludge. Or that your filtration is not adequate/not being cleaned enough. First, try to eliminate the source of the dirt (consider placing gravel or rocks on top of plant pots to prevent digging). You should begin cleaning/backwashing your filter more often and, if this does not work consider upgrading the filtration system.

‘Flocculents’ can be used to speed up this process or as a temporary quick fix. Flocculents work by binding together the suspended dirt particles sinking them to the bottom of the pond and making them easier to be caught up by the filter. You can buy flocculents HERE

‘Tea Stained’ water

This indicates that there are rotting sticks/leaves in the pond. This rotting organic matter releases ‘tannins’ into the water, giving that tea-like appearance.

Net out leaves more regularly and do more frequent backwashing of the filter. The addition of activated carbon to areas of water movement can assist in removing tannins.

Algae issues

For detailed info on the different types of algae, what causes them and how to treat it please check out our article HERE

As mentioned earlier, a bit of algae in the pond is natural. But sometimes it can be a bit much!

Green water: indicates inadequate filtration or that your UV globe needs changing! UV light kills single-celled algae that turn water green

String algae: generally occurs in spring and summer when beneficial bacteria levels are low. Early spring is a great time to add beneficial bacteria weekly

In general, water quality issues can be multidimensional, so we need to compile a complete picture of all the factors that contribute to our little pond ecosystem. The first step is to do a water test.

Test for pH, ammonia, phosphates and nitrates and let us know the results. Click here to have a look at our test kits available if you need one.

We recommend doing monthly water tests (or additional tests if you think something is not quite right!) We also provide a free water testing service at our shop if you do not have a test kit.

Just bring a water sample up in a clean jar and we can test it for you. We can have a chat about any of the other factors that might be affecting your water quality and make recommendations so that things can improve.

If you ever need the whole pond cleaned out and you live in the Sydney region, we can do this for you. We have a fish pond cleaning service so click here to find out more