Why Is There Foam in Fish Tank? (Questions Answered)




foam in fish tank

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If you suddenly come across a nasty-looking white foam floating at the surface of your fish tank, quite rightly, you might be concerned.

What is this? Will it hurt my fish? How do I get rid of it?

There are many causes of different types of foam and bubbles on the surface of your tank’s water, some of which can be far more harmful than others.

In this article, we will discuss protein foam, a type of smelly white foam found mostly on the surface of saltwater aquariums, and help you resolve the issue whilst keeping your fish happy and healthy!

What Is Protein Foam?

First, you’ll want to know exactly what protein foam is.

This particular foam forms a film-like surface that traps oxygen by creating small air bubbles that stick together. It typically appears like a layer of white scum and smells very unpleasant.

Protein foam is typically found in saltwater aquariums. However, it can occasionally be found in freshwater fish tanks as well.

If it’s smelly and appears to look sticky against the aquarium water, there’s a high chance that the issue you’re facing here is protein foam. This shouldn’t be confused with bubble nests.

Bubble nests are a layer or form of bubbles created at the water surface by some species of fish, such as betta, where their eggs are laid.

What Causes Protein Foam in Fish Tanks?

If you notice a build-up of protein foam on the surface of your tank’s water, you might also be wondering how it got there, why, and what you can do to resolve this issue.

In short, protein foam is an indicator that your tank needs a really good clean. It can result from a build-up of feces/fish waste, decomposing bodies of former tank inhabitants (yes, there may be a dead fish amongst your tankmates), and uneaten food.

The organic waste can lead to not only a build-up of protein foam but also a build-up of ammonia in the tank, which can be very harmful to your fish. So, if you notice this foam, you’ll want to do something about it!

Will the Bubbles in My Fish Tank Go Away?

As protein foam is a result of a build-up and breakdown of organic matter, if you leave it alone in hopes this issue may resolve itself, you’re likely going to do more harm than good.

As I said before, the presence of protein foam is a great indicator that your tank is in need of a good cleaning.

Is Foam Harmful to Fish?

foam in fish tank

While protein foam isn’t an emergency, it can still be harmful to your fish if left over a period of time.

As this foam harbors the oxygen from your fish’s water, allowing it to build up can cause a decrease in oxygen in your tank’s water over time, which can be very harmful, if not deadly, to your fish. The foam itself isn’t harmful,  but the indication of the foam’s presence might be.

How Do I Get Rid of Protein Foam in My Aquarium?

As I have previously mentioned, any presence of Protein foam is a good indicator that your aquarium is in need of a good cleaning. For this reason, you’ll want to ensure you’re doing more than simply scraping the layer of the foam off of the surface of the water.

If you have a saltwater tank, you’ll be able to use a protein skimmer. This is a device used to remove any organic fish waste from the tank. If you have a freshwater aquarium, however, these aren’t as effective.

But worry not, there are plenty of other ways of getting rid of the protein foam and preventing it from returning, for both freshwater and saltwater aquariums!

First, simply scoop off the foam from the surface of the water. It’s unsightly and removing it is the first step in getting the tank a little cleaner.

Next, ensure that your filter is clean and working, and begin to remove any debris such as poop and uneaten bits of food that may have settled at the bottom of the tank using a gravel vacuum.

It’s important to note that Protein foam is a direct cause of the decomposition of – you guessed it – protein!

For this reason, as sad as it may seem, you might want to consider if anyone seems to be missing. Harsh, I know, but the decomposing body of any creature will be a huge source of protein waste.

So, if any of your tankmates haven’t shown their face for a few days, you might want to have a little look around in corners, behind rocks, and inside the hidey-holes just to double-check that no one has passed away.

Other than fish, feces, and food, another key cause of protein waste can come from decomposing plants. You’ll want to check up on any live aquatic plants you have in your aquarium to see if any have died or begun breaking down. If this is the case, be sure to trim dead leaves and remove them, or, if the plant is doing very badly, remove it altogether.

Can I Prevent Protein Foam from Coming Back?

If your protein foam was caused by a deceased tankmate, first, sorry for your loss, and second, it’s likely that this won’t be a persistent issue due to the setup or hygiene of your tank.

In other words, keep up the good work! This likely just occurred just once due to the death of your fish. If the protein foam was caused by anything else, however, regular water changes, maintaining your fish tank filter, and cleaning your gravel more frequently will prevent the protein foam buildup from becoming a recurring issue.

In short, protein foam is quite a gross thing to have to deal with in your tank and can come about due to a build-up of waste. So, just clean your tank, and it (hopefully) won’t happen again!

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