If you ask me what can be the biggest obstacle between your pond and the aesthetics of it, I can answer confidently that the obstacle is the ugly-looking film. No matter how good of a homeowner you are, somehow various kinds of film end up growing and ruining the beauty of your pond.

In most cases, it’s a mixture of dead remaining algae and protozoa. These kinds of films are known as biofilms. The blooms of live algae and the pollen from plants living in the pond can also be the reason. The films might be super ugly but not much harmful.

But we can’t let our pond look like an abandoned pond, can we? So, for a better understanding of what to do with what kind of film, keep scrolling.

Different Kinds of pond films and what to do about them

There can be a million reasons behind the sudden or gradual outbreak of film in your pond. And like the number of reasons, there are numerous kinds of films decreasing the looks of your pond. Of all the kinds of films, a few are most common and seen and I can give you a few ideas about how to go about them.

You will get an idea of what kind of film is growing in your pond from the following list. Not just that, I also added a few hacks regarding how you can get rid of those films and get the beautiful look of your pond back. Let’s look at the kinds of films and what they mean.

Causes of Pond Films And How To Get Rid of It

1. Biofilm

When you start to notice a shimmering and oily coating across your pond water, that’s probably biofilm. Don’t be fooled and consider it as an oil slick because oil slick does not accumulate on every pond but biofilm does. So if you have a pond where there’s no chance to have an oil slick, it surely is biofilm. On top of everything, here’s a simple test hack for you to determine whether it is oil slick or biofilm.

Take a stick and pull it across the film. Wait for a minute and observe what happens. If you see oil swirling around, it’s oil slick. And if it’s breaking down into pieces then it’s biofilm.

Biofilms are the results of increased numbers of various biological matter present in the pond. Though the reason behind this is still clearly not understandable, researchers have come up with some of the possible environments which make your pond condition prone to growing biofilm.


As you already know, biofilms are a mixture of dead algae along with protozoa and other organic matter which are not decomposed. All of these happen if the water is a little bit less acidic indicating lower ph. Having lower ph in your pond water is one of the conditions where biofilms grow easily. In times of hot weather, biofilms grow a bit much more, especially where the temperature goes over 70 Fahrenheit. The effects that rainfall has on biofilms are yet to be confirmed.

Removing biofilms is often a very tough task and at times it might seem impossible. But one thing that has worked for many is by raising the ph level of the water in your pond. Using lime and soda ash as well can increase the number of ph in your pond water. You can add certain types of bacteria as well which are helpful in this case.

One last suggestion would be to refrain yourself from using chemicals as it might make the overall biofilms condition uglier, especially chemicals such as algaecides.

2. Algae bloom

Algae bloom is the sudden increase of algae in the freshwater of your pond. In marine water, there are various harmful kinds of algae blooms but luckily in the case of domestic ponds, the algae blooms are not that harmful. We mostly see two kinds of algae bloom in domestic ponds. One is planktonic and the other one is filamentous. Both of them are briefly described below.

  • Planktonic algae

Planktonic algae are harmless and the yellowish or greenish color of the film will give you the idea that it’s planktonic. During the warmer seasons, planktonic blooms and vanishes on its own during winter.

When planktonic blooms, it’s omnipresent across your pond but don’t worry it’s not harmful to humans. Rather it does the job of a base and is somewhat beneficial for the fishes you have in the pond. But too much of it will cause major difficulties. Because when they die and decompose, the whole process decreases the oxygen supply in water.

So you need to determine whether you have too many planktonic algae in your pond or not. To do that, attach a string to a tiny object and sink it in the water. Make sure the string is at least 18 inches or longer and put a mark on the 18th-inch spot. Sink the object deep enough so the water touches the marked part.

At this stage, if you can still see the object, you have no headache. But if you can’t see properly or can’t see at all, you need to take control of this algae asap.

The best way to deal with planktonic algae is to reduce the nutrients present in the pond water. In order to do that, make sure no animal defecates anywhere near the pond, and fertilizer from your garden should not enter the pond water.  Without nutrients, Planktonic algae will not grow much and on the other hand, aeration can come in handy as well.

You can go for chemical substances as well but the algae grow back once the chemicals decay. The mechanical process of removing is not applicable either as the planktonic algae is very tiny.

  • Filamentous Algae: Green Film on Pond

This kind of algae is more like a plant and often appears as a mat on the top of your pond water. This kind of algae is mostly harmless and found in either green color or blue. But it’s often packed with bacteria so it’s better not to jump in a pond with filamentous algae for you.

When filamentous algae are less in number, they form small mats here and there in your pond. And at this stage, they are totally harmless. But if you don’t provide proper attention, they can grow and cover up the whole pond very fast. As a result, sunlight won’t enter your pond and the oxygen will decrease. This condition is not ideal for the fish you have in your pond.

If you are in this situation, you can follow the instructions given for planktonic algae. Cause both of these are pretty much the same in nature, so the cure to these is the same as well. But I can give a few different ideas as well so you can fight filamentous algae.

Adding tilapia fishes can be a great solution to your filamentous algae problem. Blue tilapias are especially very fond of eating this kind of algae. So if you add a few blue tilapia, they will eat all the filamentous algae and somewhat solve your problem for the time being.

But that’s not the ultimate solution because as you know tilapia is a tropical fish and can’t survive in winter. So, you should decrease the various nutrients of your pond water by winter to get rid of it for good.

And the last option would be removing it mechanically. Staying careful you should go about this process and remember this is just a temporary solution because this kind of algae will surely grow again.

3. Pollen

A lot of pollen on the surface of your pond water will surely make the pond look super ugly. It’s not harmful but the way it sticks across the surface of the pond water is an eyesore.

Due to the surface tension, it keeps on floating on the water even though it’s a very thick layer. Until you do something about it, pollen will cover all over the pond surface and destroy the overall look.

It has the easiest solution regarding how you can get rid of it. The solution is to wait for rain as the rain will help break surface tension. As a result, the pollen will go down and escape via exit pipes.

And if you are in a hurry, you can use hose pipes instead. As long as you use anything that can make the water surface move, the pollen will get down.

An Ultimate Solution for Films: Aeration

Aeration is the process of adding oxygen to your pond water. It can be done in a few ways, but the most common way is by using a device that can compress air from the surface and get it inside the water as bubbles.

Aeration is needed because in most of the aforementioned cases, it can help. You can install it on either the subsurface or the surface of your pond water. Aeration works by mixing air with water giving the water that extra bit of much-needed oxygen. If you have a small pond, you don’t need machinery. A simple fountain or a waterfall can get the work done.

But in the case of larger ponds, you need those devices. These devices release lots of bubbles filled with air into your pond water. These bubbles are made up of compressed air taken from the surface.

There are lots of options available in the market from which you can get an aeration device. You can install it yourself or get it installed by someone who’s an expert. Given the need for this device and other benefits, this will be one of the most valuable investments of your pond life.

Another Effective Solution: Pond Skimmer

Using a surface skimmer will get rid of the pond scums quite effectively. There are lots of surface skimming devices available in the market. Select the once which is suitable for the size of your pond and you are good to go.

Should you use chemicals to fight films

Chemicals such as algaecides or herbicides are very effective no doubt about that. But we should look past that and see what other issues they are bringing to your pond. First of all, let me tell you that any kind of chemical which is used to destroy algae or films can destroy the overall ecosystem of your pond.

You don’t want to end up killing the fishes in your pond to destroy the algae or film. The bad effect of chemicals doesn’t stop here. Then the dead algae and fishes will make more biofilm grow, and the whole pond will be covered with biofilm once the chemicals have decayed.

So considering all the pros and cons, my suggestion would be not to use chemicals at all. Keep this option as the last resort.

Final Words

Now you have a better idea about what different kinds of films mean and what you can do about those. Just don’t forget to be patient while dealing with these films and try not to use chemicals. The patience will be worth it when you see the pond after removing all the films.

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