How fish stay afloat
Aquariums afford hours of soothing entertainment


Keeping fish is more popular than ever. While it may be a bit of a stretch to call them pets, they do bring hours of enjoyment to those that own them. Yes, they can be a fair amount of work to maintain, but the rewards are usually worth it. Just kicking back and watching them can have a soothing effect on all who observe them. Lots of people use aquarium scenes as screen savers and some people have been known to place a video cam directly in front of their aquariums and shoot a few hours of footage to play back later on big screens. But how exactly is it that fish stay afloat? Read on and find out.

How Fish Float

In order for objects to be buoyant, there needs to be air or material lighter than water. Fish have an advantage because they come equipped with their own internal air chambers in the form of swim bladders that basically renders them lighter than H2O. Because fish require submersion, they have to have a way of controlling that handy dandy feature that allows them to float in the first place. Swimming deeper is easily accomplished by releasing gas from their swim bladders and just the opposite occurs when they want to go higher. They simply take in more gas. Pretty simple, really.


How Fish Float, Have You Ever Wondered?
Goldfish may have trouble regulating their swim bladders

Types of Swim Bladders

It should be noted that not all fish have swim bladders. Some species, such as tuna, don't have swim bladders. The lack of this feature means they must always swim near the bottom. But, for fish that do, there are two main types of swim bladders. Some fish have a connection between their esophagus and their swim bladder. Due to this, they swallow air in order to inflate the chamber. The second main type operates through a system of tiny blood vessels located in the walls of the swim bladder. These vessels then regulate the amount of gas within the chamber.


Certain fish, like the ever popular goldfish, can have difficulties regulating their swim bladders. That's because they are fish that fall into the first type of swim bladder as outlined above — you, remember, the ones with the esophagus that's connected directly to the swim bladder. The reason they might experience trouble at times is usually connected directly to humans and their feeding techniques. So, what gives? Well, it's not all that uncommon for their esophagus to get clogged from dry food that expands as it gets wet. You can liken it to a sponge taking on water. When fish try to swallow it, it can block the duct. Without the ability to deflate or inflate their swim bladders can become stuck, leaving them unable to rise or descend.


Keeping fish healthy and afloat
Keep your fish healthy & afloat with a high water quality

Keeping Fish Afloat

Besides a clogged duct, there are things that could be going on like diet, bacteria or a virus that could be presenting a problem, but a blocked esophagus, at least in fish with a direct connect swim bladder, is the most common reason. Fortunately, this is easily prevented, if you know what to do. First off, if you're using dry food, try pre-soaking it first. Second, consider changing your fish food from dry to gel based. Third, keep the tank's water quality at a high level. Besides helping them stay afloat, this last tip will alleviate a myriad of other fish-tank related problems at the same time.

Now that you know how fish float and how to keep your own fish that way, I'll bet you feel smarter already!