If you notice foam or bubbles on top of your fish tank water, don’t panic.
This happens often and can be caused by different things. Some are safe, others could harm your fish.
Why Do Foamy Bubbles Form?
Foamy bubbles form due to gases trapped in a thin liquid layer.
It can be any gas, like oxygen or carbon dioxide. These gases can get trapped in a thin layer made of different things like:
- Agitated water,
- Soap,
- Protein,
- Fish saliva, and
- Fish Medications.
The gases get trapped inside these layers when they’re shaken up or disturbed, forming bubbles.
Let’s now take a closer look at each of the causes foamy bubbles in a fish tank…
1. Agitated Water
Bubbles are formed when water is shaken or stirred up; they’re simply pockets of oxygen in the water.
This can happen in a few situations:
- When you add water to a fish tank, it can stir up the water and cause bubbles. This is normal and not harmful. To avoid bubbles, pour the water slowly onto a plate placed at an angle in the tank. This way, the water flows gently into the tank instead of causing a splash.
- If you have a device like a spray bar or powerheads in your tank, they might stir up the water enough to create bubbles. Usually, this doesn’t make a lot of bubbles and the bubbles that do form are big and disappear quickly.
2. Soap
Soap bubbles can form in your fish tank if cleaning materials, like a water bucket or scrubbing brush, have soap residue on them.
This creates a filmy layer of bubbles on the water surface, similar to the bubbles seen in a sink full of soapy water. These bubbles can harm your fish.
If this happens, you need to act fast to save your fish. Move your fish to a different tank or a clean bucket filled with dechlorinated water. The water should be the same temperature as your fish tank.
Empty the soap-filled fish tank and rinse everything inside it thoroughly. You also need to clean the filter and replace all the filter media and pads since they might have collected soap.
Then, fill the tank with clean water and put your fish back.
To prevent this from happening, have a separate set of cleaning tools just for your fish tank. This way, you won’t accidentally introduce soap into your tank.
3. Protein
Protein foam is caused by organic waste like fish poop, dead fish, and leftover food. These wastes create a film that traps oxygen and forms small bubbles, producing a stinky foam.
This is more common in saltwater tanks but can also happen in freshwater tanks. Although it’s not an emergency, it can lower the oxygen levels in your tank if not addressed.
To take care of protein foam, you need to clean your fish tank. Check if your filter is clean and use a gravel vacuum to remove any waste.
Also look for any decaying fish hidden in the tank since they can be a major source of protein foam. Remove the fallen leaves from plants too as they can also contribute to protein waste.
If you have a saltwater tank, you can use a protein skimmer to remove excess proteins. But these don’t work in freshwater tanks.
Regularly changing the water, maintaining the filter, and cleaning the gravel can prevent protein foam from becoming a problem.
4. Fish Saliva
Bubblenests are foam patches created by male Labyrinth fish like Betta or Gourami. They make these nests by blowing bubbles of sticky saliva into a floating foam mat.
These nests are used to attract female fish, even if there aren’t any females around.
A bubblenest is a good thing. It shows that your male fish is happy and healthy. It’s also not harmful to any other fish.
Be careful not to mess up these nests. If you do, it can stress out the fish that made it, even if it’s the only one in the tank.
5. Fish Medications
When you put medicine like antibacterial treatments in a fish tank, it can change the water.
This change can make a foamy layer of waste stuff build up on the water’s top.
This foam doesn’t hurt anything and should go away in a few days after you stop giving the medicine.
What Are Pearling?
Pearling are the little clear bubbles that form on the leaves and stems of water plants.
This happens when the plants are making food or doing photosynthesis.
Experienced aquarists call these bubbles ‘pearling’ and consider them a good sign that indicates the plants are healthy. These bubbles don’t hurt the fish.
