Fish have fascinated humans for centuries—from shimmering schools that move as one, to solitary deep-sea dwellers glowing in the dark. But beyond their beauty lies a world of curious behaviors, survival tricks, and environmental importance.

You will find in this article answers to the most essential questions people ask about fish—whether you’re wondering how they sleep, breathe, or interact with their watery world.

Think of this as your guide to decoding the mysteries of fins, gills, and underwater lives. Let’s swim through the facts that keep fish lovers hooked.

Important FAQs about Fish

With this guide, let’s Try to find answers to the next questions:

• Do Fish Fart?
• How long do fish live?
• How can you tell the age of a fish?
• Do fish sleep?
• What is the world’s largest fish? The smallest?
• What about the Mysterious Herring?

Do Fish Fart?

Fish flatulence may not be one of those most common marine mysteries you are dying to know the answer to, but at the same time it has never failed to create a perplexed look on the recipients face and get everyone thinking…do they?

So do fish fart? Well, let’s first explain what a fart is. Farting is considered the by-product of digestion (when gases expelled solely through the rear-end). So, we can say that most fish don’t fart (with the exception of herring and sand sharks).

Most fish adjust their buoyancy by inflating and deflating their bladder through the mouth or gills (This process is sometimes misread as a fart). For instance, sand tiger sharks gulp air into their stomachs at the surface which they then discharge out the back door to attain a desired depth.

Actually, Fish release digestive gases mixed with feces in jelly-like tubes—sometimes they eat them again. Point being: no farts.

How Long Do Fish Live?

Some of the smaller reef fish can have a lifespan of a few weeks or months while some other species like sturgeons can live until reaching 50 years or more.

Many fish live around 10–20 years in temperate waters, but some creatures—such as the Marion’s tortoise (152 yrs), fin whale (116 yrs), and deep-sea clam (100 yrs)—live much longer.

How Can You Tell the Age of a Fish?

We can determine the age of the fish by two ways. The first, by growth “rings” on its scales, and the second, which is the more reliable method, by the ringlike structures found in otoliths (small bones of the inner ear). Like tree rings, these bands reflect seasonal environmental shifts.

A series of fine rings are laid down in scales for each year of life in summer, the rings grow faster and have relatively wide separations. In winter, slower growth is indicated by narrow separations between rings. Each pair of rings indicates one year.

Do Fish Sleep?

It all depends on what you mean by “sleep”. Our dictionary says that sleep is a period of rest in which the eyes are closed and there is little or no thought or movement.

That is, sleeping means closing your eyes and resting. The first thing we notice is that most fish don’t have eyelids (except for sharks). Also, there are some deep ocean fish that never stop moving, a great many fishes live nearly motionless lives and many do so on a regular diurnal/nocturnal cycle, some active by day others by night.

Some float in place, some wedge themselves into a spot in the mud or the coral, some even build themselves a nest. They will still be alert for danger, but they will also be “sleeping.” Dolphins sleep with one eye open!

What is the World’s Largest Fish? The Smallest?

The largest is the whale shark, which grows to more than 50 feet in length and may weigh several tons; second largest is the basking shark, which may measure 35 to 40 feet long.

The smallest fish in the world are the pygmy goby and the Luzon goby, from the Philippines, which are only one-half-inch long when they are full grown. It seldom is longer than a half inch at adulthood, yet is so abundant it supports a fishery.

By considerable measure, the largest known marine mammal and animal on Earth is the blue whale. Mature blue whales can measure anywhere from 75 feet (23 meters) to 100 feet (30.5 meters) from head to tail, and can weigh as much as 150 tons (136 metric tons).

What about the Mysterious Herring? From a scientific perspective

In 2003, biologists from the University of British Columbia discovered a bizarre method of communication among Pacific and Atlantic herring: what appeared to be, and even sounded like farting. The scientists heard underwater signals at the same time as they observed bubbles coming out of the fish’s rear end.

Upon further research, they discovered that the fish themselves were controlling the release of bubbles to keep moving as we said before, which was also responsible for the audible sounds accompanying the bubbles. In a clever use of onomatopoeia, the sounds and bubbles were dubbed FRTs—Fast Repetitive Ticks.

The study produced three findings:

The more herring in a tank, the more FRTs were recorded. This indicated to the scientists that the herring were indeed using the FRTs as a means of communicating with each other.

The herring only use FRTs after dark. This meant that this method of communication was viable even when the fish couldn’t see each other in the dark, enabling them to stick together at night.

Only the herring can hear the FRTs. The signal that herring use to communicate cannot be heard by predators or most other fish, allowing them to stay together in a shoal without risking detection.

So, as it stands, that is the latest on the age old question of do fish fart. Do they release gas in the same manner as humans and other animals do? The answer is no. Do they have farting contests with their friends in large groups? It kind of seems like they do.