Can Nemo Fish Live in Freshwater? Only if You Like Fishy Funerals.

6 min read


The popularity of the ‘Finding Nemo’ movie has helped skyrocket the popularity of the clown fish, the type of fish Nemo is, and created a huge demand for clown fish in aquariums.

My wife and I love the movie, so we have been doing a lot of research and one of the questions we had to answer was,

Can Nemo fish live in freshwater? The short answer is that Nemo fish can not live in freshwater because they are marine or saltwater fish. Their natural habitat is the salty ocean water and because of a process called osmosis, Nemo fish would die in freshwater because of the lack of salt. Their cells would take in too much water.

This is actually a very interesting process, so let me explain further and then I will let you know what you need to do if you want a Nemo fish at home…

Most fish can only live in saltwater or freshwater based on how much salt their bodies can handle,

“Salinity is the saltiness or amount of salt dissolved in a body of water, called saline water. Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water.”


Nemo fish (clown fish) have cells that are called hypotonic, which means they have less salt than the surrounding water. They live in Saltwater that is called hypertonic because the water has more salt than the clown fish.

Clownfish may have less salt or sodium than saltwater, but they still have a lot of water that they need to survive. To understand this better we need to know what osmosis is…

A dictionary will tell you, “a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.”

In the case of clown fish, they have a membrane and the inside of there body has less of the solvent which is sodium/salt. So, because of osmosis, clown fish lose more water than they take in because their body has the lower concentration of the salt solvent.

To keep from losing too much water, clown fish are constantly drinking water to keep enough circulating through their bodies. This leads us to putting a clownfish in freshwater…

If you put a clownfish in freshwater it will die because of osmosis. In freshwater, the membrane will let too much water pass into the clownfish’s body because now the clownfish will have more of the solvent which is salt/sodium. Eventually, so much water will fill their body until they look like a water balloon and everyone knows what happens to water balloons.

Even though they are both fish, saltwater and freshwater fish have a completely different body chemistry. Since we’re talking about this we can easily answer the opposite question, …

What would happen if a freshwater fish were placed in saltwater?

On the other end of the spectrum, a freshwater fish is hypertonic, which means it has more of the salt salute than the surrounding freshwater. Because a freshwater fish is hypertonic it must constantly urinate to make sure it doesn’t take in too much water.

The freshwater fish has a body that is designed this way so if they are put in saltwater, they will urinate too much and lose to much water. They will eventually die of dehydration.

Okay, now that we understand the difference between saltwater and freshwater fish in relation to their surrounding water we can answer your most important question…

How to Keep a Clownfish at Home

First of all, since we have established that clownfish live in a saltwater environment, we know that our clownfish will need a saltwater environment in your home as well. This leads to a basic rule of thumb when it comes to home Aquariums – your basically just trying to mimic their natural habitat in your aquarium.

With that being said, there is a lot of info out on the web that talks about saltwater aquariums being harder than freshwater and that beginners should start with freshwater aquariums. However, the only real difference, at least with clownfish, is to learn how to mix saltwater so, relax.

So, if you are going to start a saltwater aquarium, just make up your mind to do your homework, learn how to do everything and just do it right. If you really are tentative or too unsure then just start with a freshwater tank and get a clownfish look a like that can live in freshwater.

Here are some freshwater fish that look like clownfish –

Clown Loach – Larger fish. These fish are much larger so only use a 5-foot tank or larger. They do have the orange and black stripes like Nemo.


Tiger Barb – Should be kept in a group of at least 6 or more with other tiger barbs but not with fish of other species because of their aggression. Need at least a 30-gallon tank. They are more of an oval shape but have the black and orange stripes like nemo.

TigerBarb PetAquariums Can Nemo Fish Live in Freshwater? Only if You Like Fishy Funerals.

Nemo is actually called an Ocellaris Clownfish. Setting up their saltwater tank for clownfish isn’t as difficult as some people think but you do need to follow the proper steps. You need at least a 20 gallon tank and two clownfish is recommended because they do well in pairs but any more than that and you will have trouble. A 30-gallon tank is even better because it will take longer for the water to contaminate and you will have more room for a suitable tank mate, such as:

You need the basic aquarium setup like:

Proper Diet

Clownfish are omnivores, so they can eat a wide variety of foods like:

Proper Tank Settings

  • Ideal Temp: 76 -78 Fahrenheit
  • Salinity: 1.020 – 1.026 sg
  • Ph: 8.1 – 8.4
  • Alkalinity: 7 – 12 dkh
  • Nitrates: 20 ppm or less

Once you have you have your aquarium setup it usually takes 4 – 5 weeks for your aquarium to run through the natural system before it is safe for your fish, especially if you add live rock. It will probably cost you between 3–500 dollars, depending on the quality of equipment that you choose

After you add your fish you will have to do regular maintenance like feeding daily observation to watch for cloudy water or sick fish, regular water changing, regular filter material replacement (not the housing).

Even if you are hesitant about a saltwater aquarium, clown fish are one of the easiest fish for saltwater setups. Even if you buy a wild caught clownfish, they are used to living in close proximity with anemones just like in the movie ‘Finding Nemo’, so they don’t need a lot of space to survive.

However, don’t fret about adding an anemone to your tank. Most aquarium clownfish are bred in captivity now, so they are not raised with anemones.

The reason for this is because the movie caused the demand for clownfish (as an aquarium pet) to skyrocket so much that many of them were captured in the wild and their population in the ocean was lowered dramatically. This in turn can harm the ecosystems that fish are a part of.

So, regardless of the current situation, I always recommend making sure that you are buying captive bred fish so that ravaging of fish species in the ocean doesn’t happen in the future.

Once you get your clownfish settled into to their new home, they can be one of the funnest fish to interact with. Check out our article here entitled: How Do I Play With My Pet Fish?

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Pet Aquariums

Have you any questions?