Everybody knows that humans can drown when their lungs fill up with water and they stop to take in oxygen, but what about creatures that don’t have lungs and instead have gills?
Can goldfish drown? No, goldfish cannot drown, but it can suffocate underwater. It can suffocate because of insufficient oxygenated water, damaged gills, or because of it getting stuck underwater. For goldfish to breathe underwater it needs to move so that water can circulate over its gills and it can take-in the oxygen from the water. Just like all fish, goldfish too; need oxygen to survive, and if the water it’s in runs out of oxygen, then it will die. For example, if you leave a goldfish in a small bowl it will eventually run out of oxygen if there is no working filter connected.
A better term to use for fish that “drown” in water is suffocation. Drowning is when the lungs fill up with water, and they are unable to get oxygen for the body. Fish can perish from lack of oxygen, but to be more accurate it should be termed as suffocation.
How Do Goldfish Suffocate Underwater?
Goldfish can suffocate in several different ways because they need oxygen to live.
If you take a goldfish out of the water, it will suffocate because there is no water to move over its gills and it can’t pull oxygen out of the air.
Here are various ways in which goldfish can suffocate underwater:
- Not enough oxygenated water or too much carbon dioxide in the water.
- Damaged gills.
- The goldfish cannot move, and they need water pushed over their gills.
Let’s take a deeper look at each of these…
Recommended Further Reading: How To Take Care Of A Goldfish? (Goldfish Care In 3 Simple Steps)
Not Enough Oxygenated Water, Or Too Much Carbon Dioxide
Similar to humans, fish must expel carbon dioxide when they breathe.
If they are in an area such as a small tank where there is too much carbon dioxide build-up and not enough oxygen, then they will die.
This is highly unlikely to happen in nature unless certain ponds have too many plants that throw off the oxygen levels and kill the goldfish.
But the goldfish in tanks and aquariums will die easily if the tank or aquarium is not able to cycle water efficiently.
Oxygen is dissolved into the water at the surface, but the surface area of a tank is limited.
So many times air pumps need to be installed in tanks to bring deoxygenated water to the surface where it can be refilled with oxygen for the goldfish to eventually breathe.
Interesting Further Reading:
- Can Goldfish Live In Well Water? (Yes and No, Here’s Why)
- Can Goldfish Freeze and Come Back to Life? (No, Here’s Why)
- Can Goldfish Choke? Yes – And Here’s How To Avoid It
If the gills of the goldfish get damaged, it will become that much harder to breathe-in the much-needed oxygen, and this increases the likelihood of suffocation.
Gills can get damaged from attacks by predators and other marine animals.
This could also result from chemical damage such as ammonia or nitrates.
Fish With Ram Ventilation Stop Moving
The last way goldfish could suffocate underwater is because they rely on ram ventilation to breathe.
If these goldfish are put in a position where they cannot move forward anymore and push water over their gills, then they can’t get their needed oxygen.
This could occur by trapping goldfish in nets where they cannot move.
Goldfish can’t die from “drowning,” but they can surely die from lack of oxygen and through suffocations.
Remember that this is a very real possibility when you plan on getting goldfish or if you already have them.
Related Further Reading:
- How Do Goldfish Adapt To Their Environment? (Wild + Captivity)
- Can Goldfish Lose Their Black Markings? And Why It’s A Good Sign?
Anatomy Of A Typical Fish
Fish need oxygen because they have organs that require it, just like humans and other mammals.
The body of a fish has a heart, a brain, and cells that require oxygen to function.
The fish’s heart pumps the oxygenated blood all throughout the body, which brings oxygen to the brain.
Additionally, fish have kidneys and livers that work to break down fats and waste materials.
Here is a list of the inner organs of a fish.
- Swim Bladder,
- Urinary Bladder,
The liver is very important for the destruction of old blood cells; it enables new blood cells to be created so that the fish can continue getting oxygen.
The spinal cord provides a structure to the fish’s entire body, just like all vertebrates.
The spinal column of the fish also relays information about the body to the brain and transmits the signals from the brain to the rest of the body with a whole network of nerves and nerve roots which are located all along the spinal column.
Fish also have an organ known as the swim bladder; this helps them keep control of their position in the water.
The swim bladder fills up with gas to aid the fish in maintaining neutral buoyancy and keep their position.
Some fish don’t have swim bladders; this means that they need to swim continuously to maintain their position in the water or else they will start to sink towards the bottom.
How Do Gills Of A Fish Work?
Fish have lots of organs that humans have, but since they don’t have lungs, they instead have organs called gills.
The oxygen of fish comes in through the gills. Gills are made up of groups of cells known as the epithelium.
Arteries deliver deoxygenated blood to the epithelium, and as water is moved across the epithelium’s membrane, the oxygen that’s dissolved in the water is absorbed by blood vessels and veins.
Most commonly, fish will have four gills on each side of their body, which consists of many interlinking columns of cells.
Depending on the fish they will push the water over their gills in many different ways.
Usually, fish push the water by widening the skin flaps that are right on top of the gills.
To do this you will see fish open and close their mouth.
When they lower the bottom of the mouth, it causes the skin flaps to widen, and water comes in.
When these fish close their mouths, the water becomes trapped within the gills, and all the oxygen is pulled out.
The water without any oxygen left is expelled through an opening in the fish known as the operculum.
Oxygen Levels In Air And Water
The oxygen levels dissolved in the air are much lower than the oxygen particles in the air.
Air has about 210,000 parts per million of oxygen or 21% oxygen generally speaking.
Compared to this water has around 4-8 parts per million of oxygen.
This stark difference means that fish’s gills have to be fairly large to keep it constantly supplied with oxygen.
Warm-blooded creatures need more oxygen than cold-blooded creatures; fish are cold-blooded, so they need less.
However, cold-blooded creatures also have a slower metabolism than warm-blooded creatures which is partly why they need less oxygen.
Some Fish Have Five Gills
Some cartilaginous fish like sharks and rays have 5-gill slits on each side of their body.
A cartilaginous gill arch helps support these slits and maintain the fish’s overall body structure.
Many species of sharks need to breathe by forcing water over their gills at all times, which they do by swimming forward constantly.
These same sharks rarely have swim bladders as well, which means they need to keep swimming regardless or else sink to the bottom.
How Do Fish Deal With Salty Seawater?
Saltwater fish can expel the excess sodium from their bodies.
Large amounts of their blood have to exchange carbon dioxide and oxygen. This process is also exposed to really salty water.
Freshwater fish reverse this process, they need to keep extra sodium to keep their overall levels high and they, therefore, excrete extra water.
All these fish contain chloride cells that regulate this balance of salt and maintain homeostasis that keeps their body functional and healthy.