If you find bubbles on top of fish tank water, don’t panic – it could be a number of things. Even though these bubbles or foam will not harm your pet fish, you should still be aware of what causes bubbles on top of fish tank and how to get rid of them.
Sometimes fish tank bubbles are normal, and other times it could be due to one of five aquarium issues. It could simply be a bubble nest, soap residue, bubbles formed by oxygen in the water, agitation from the filtering system, or protein accumulation.
Here we will explain each of these aquarium challenges and how to remedy the situation.
What is a bubblenest foam in an aquarium
Some male fish create a sticky, foamy bubblenest to attract the female for mating. When your male fish are creating bubblenests, it is an indication that they are healthy and content. The hope is for a female to swim into the area to begin the mating process. So, it is best to leave these bubbles undisrupted or else you may stress out the male foam builder.
These clusters of bubbles on the surface of your fish tank are part of the breeding process of betta fish or “labyrinth fish”.
Betta fish are very territorial and are even called Siamese fighting fish. In addition to the bubblenest being an attraction to the female Betta, it also serves as hatchery to safely secure eggs within the bubbles. This means that the eggs are constantly kept moist and oxygenated. This is an important feature because the natural habitat and breeding grounds of betta fish is often a shallow, dirty water pond that does not have much oxygen.
It is the male betta fish’s job to protect the eggs after the female betta has released them. They will guard the bubblenest with ferocity and even search out, find, and replace any eggs that have fallen from the bubblenest.
Bubbles in fish tank after water change
After changing the water in your home aquarium, you may notice bubbles on top of fish tank or on the walls of the fish tank. When you see fine, micro bubbles covering the glass and other tank surfaces, it is likely due to the rapid change in water temperature. Cold water holds a lot more oxygen than hot water, so when you add cold water to your tank, the rapid change in temperature can cause oxygen to vacate the water in the form of air bubbles.
These bubbles should disappear within a few days, but if they bother you, simply wipe them away.
These same type of bubbles may appear on your aquatic plants as they produce oxygen through the process of photosynthesis. What happens here is the aquarium plants will feature pearl-like bubbles on the leaves and stems as photosynthesis converts CO2 and other nutrients into oxygen bubbles. These bubbles are completely harmless and actually show that your plants are healthy and growing well.
Water agitation from the filtering system
Air bubbles on top of fish tank water can easily form when water is agitated. And this can happen hen you top off or when you’re filling the aquarium tank. The agitation of the water pouring into the aquarium is enough to cause the water to foam or bubbles to appear. This is normal and even happens at any source of water agitation with the tank including the water filter.
The solution here is to add water more slowly or allow the water to slide down an angled plate into the tank instead of forcefully splashing. These air bubbles will not harm your fish, and they should dissipate rather quickly.
If the water is foamy and you have a spray bar, it may be that the spray bar is generating enough pressure that the water foams. This is actually quite common in saltwater aquariums. Try adjusting the flow of your filter or spray bar to produce less water agitation. But make sure your type of fish prefer a slower water current because some may not thrive in a tank with too little or too much water flow.
Protein accumulation can cause bubbles
Another cause of white foamy bubbles covering your fish tank could be the result of protein-based waste. When fish leave excrement, some of the waste material is left and can coat small air bubbles. This causes the bubbles that would normally dissipate to stick together in a foul smelling foam. While it can happen in freshwater tanks, it is more common in saltwater aquarium systems.
If protein foam is the cause of bubbles on top of fish tank, then it’s time to give your aquarium a good cleaning. Also, inspect the filter to make sure it is clean and remove any floating or gravel debris from the water. Protein accumulation that causes white foam or bubbles can be eliminated with protein skimmers that work to remove excess protein from the surface of the water in saltwater tanks.
If a fish has died and disintegrating without you noticing, then this will be another source of rich protein. Always keep count of your fish on a daily basis to make sure none are missing. A decaying plant or a hidden, dead fish are usually the source of the white foamy bubbles that are protein-based waste. Change the aquarium water regularly and maintain your aquarium filters to eliminate protein foam in your tank.
Leftover soap residue
If you have recently cleaned your fish tank, then leftover soap residue can form bubbles, especially when the water is agitated. Make sure the tools you use to clean your fish tank are not used for other cleaning purposes. This is especially true of the scrubbing pads and water bucket you use. Even a small amount of cleanser can cause rainbow-tinted bubbles to form within the tank.
If your aquarium does become tainted with soap, then it will need to be drained, rinsed, and re-filled with clean, dechlorinated water. Make sure the water approaches the same temperature as the previous water before returning your fish. If soap is the culprit, then even your filter and filter pads may have to be switched out or throuhghly cleaned.
How to get rid of bubbles in fish tank
- If protein foam is the culprit, then give the aquarium a good cleaning. Replace or clean the filter and remove any dead plants, leaves, fish, or other debris in the aquarium using a gravel vacuum.
- If it is a bubblenest, leave these bubbles undisrupted or else you may stress out the male bubble foam builder.
- When bubbles are due to oxygen-rich water, they should disappear within a few days, or you can simply wipe them away.
- When bubbles occur during a water change, add the water more slowly or allow the water to slide down an angled plate into the tank.
- If the white foam is due to soap in the aquarium water, then the aquarium must be emptied, cleaned, and rinsed with fresh water added.
Finally, air bubbles that are generated by your filter can eventually build up to where bubbles are floating on the water’s surface or any other place where they can stick to. Inspect where the water filter outlets or returns water to the aquarium. This is likely the cause of air trapped with the water, forming bubbles that float around your tank. You may need to more water to your aquarium until the water level is in line with your filter outlet.
If you have a high force of bubbles entering the tank, the impact on small fish can be deadly. And, if you’ve added an air stone to increase the amount of dissolved oxygen in the water, depending on the type and size of your fish, the air bubbles generated by an air stone can distress some fish.