Can You Breed Goldfish In Saltwater?

Hi, this is your friend Clifton Ervin, the founder and chief editor of this site, Aquariumwolf. I completed my graduation in marine biology and became...Read more

The goldfish is a freshwater fish that can be kept as a pet in homes. Freshwater fishes are naturally found in water bodies with the least salinity. They are native to East Asia and are now regarded as a pest in parts of North America due to overpopulation. But in extreme cases, someone may like to know if you can breed goldfish in salt water, given their natural habitat.

Breeding goldfish in salt water is difficult due to their nature. The body of a goldfish undergoes osmosis in a highly salty environment. This process removes water from the body cells of the fish resulting in dehydration or death in severe cases.

This article focuses on whether or not you can breed a goldfish in salt water. Keep reading to find out more interesting facts about the goldfish.

What Happens If You Put Fresh Water Fish In Salt Water?

Placing a freshwater fish in saltwater alters its osmoregulatory process. So, in most cases, such an action will result in certain death.

What happens if you put fresh water fish in salt water

Saltwater fishes have hypertonic cells that help them maintain a proper salt and water balance in their cells. The general belief that all fishes can survive in any water is a false assumption.

This YouTube video will reveal some eye-catching facts about what happens to freshwater fish in salt water.

But some factors can make certain water types suitable for different fishes. Find them below.


Osmosis is simply the movement of substances from a region of higher concentration to a region of lower concentration. Osmoregulation is how living things regulate osmosis to prevent cell damage.

While trying to regulate their body cells to the salty environment, the freshwater fish will lose water via their skin. It will absorb excess salt and lose its water content to the surrounding saltwater. This leads to dehydration, and the fish could die by staying longer inside the saltwater.

Saltwater fishes in freshwater will face a similar challenge as excess water will get into their cells, causing death.


Another reason freshwater fish won’t survive in saltwater is tonicity. There are three types of water based on tonicity:

  • Hypertonic
  • Hypotonic
  • Isotonic

Saltwater is hypertonic to the body of freshwater fish. This implies that the solute particle content of the water is higher than that inside the cell of saltwater fishes. This makes the fish lose the water from their body to the water around them via osmosis. But saltwater fish will drink large volumes of water to stay hydrated.

Freshwater is hypotonic to freshwater fishes. Goldfish will have a higher salt content when placed in freshwater than their surroundings. During osmosis, there is a continuous absorption of water into the body. To survive this continuous inflow of water, freshwater fish must remove excess water frequently.

However, there are some species of fish that can adapt to both fresh and saltwater habitats. These fishes are known as euryhaline fish. The Salmon is one example of them. They migrate to a different habitat during the breeding season.

Goldfish in saltwater

Putting goldfish in salt water results in quick death in most cases. However, if the fishes adapt to saltwater, they usually grow too large and become a menace to other fishes.

Goldfish in saltwater

They eat the eggs of other fishes and promote the growth of algae in the ecosystem. However, it could be tough for them to survive in an environment with a high salt concentration, like the sea.

Moderations for goldfish to live in salt water

You can apply some measures to aid a goldfish in salt water. The process requires a controlled environment like a fish tank where you can lower the salt content of the water.

The process of removing salt from a water content is known as desalination. Some popular desalination methods include:

  • Distillation
  • Boiling
  • Reverse osmosis
  • Filtration

The bottom line is that goldfish will undergo severe stress in a highly saline environment. This will ultimately lead to death in a few minutes. The cells will become oversaturated with salt, so their body cannot excrete excess amounts.

However, the moderation of salt in a controlled environment like a fish tank might be beneficial. It could help them fight bacteria and also combat some diseases.

What Is The Perfect Environment To Keep A Pet Goldfish?

Goldfish thrive better in cold water, at 62-72 degrees Fahrenheit. They also do well in alkaline water with a pH of 7.0-7.4. Adding plants to your fish tank is also great for them. But such plants must not be a poisonous specie.

What is the perfect environment to keep a pet goldfish

Sufficient oxygen levels must be a priority. An air stone will come in handy for providing oxygen. Also, ensure that your fish tank is clean and safe.

Goldfish do not require much care. The basic maintenance will ensure they remain healthy. Also, feed the fish regularly and avoid touching them as you may remove their protective slime coating.

How To Keep Your Goldfish Tank Clean

Every pet requires care and attention from its owners and the goldfish is no exception. You can employ the following methods to ensure its enclosure is clean.

Use filtration:

Use a quality filter to ensure clean water is always in your fish tank. A biological filter will be your best option in such circumstances. Buy a filter that is specific to the size of your tank.

Include other fish:

Goldfish prefer cold temperatures. So, you can include other cold-loving fishes. Goldfish are not very active and can be paired with fishes like plecos, which eat algae.

Use a siphon:

Its main purpose is to remove gravel and other annoying debris to keep your tank water clear. Leaving debris in your tank can lead to health problems for your goldfish.

Try cleaning products:

This should not be a regular option to avoid disrupting the ecosystem. However, you can do a periodic cleaning using cleaning agents to do a thorough job.

Make sure your tank is properly cycled:

Set up your tank with a working filtration system. You should cycle your tank for up to a month before adding fish to it. This will help create a comfortable environment for them.

Freshwater Vs. Saltwater, What Is The Difference?

About 71% of the Earth is covered in water, with the oceans accounting for 96.5% of the water bodies. The largest water bodies – the oceans and seas – are saline in nature.

Freshwater vs. saltwater

The difference between saltwater and freshwater is the high salt content in the former. Freshwater contains lower than 1% of salt. Saltwater has a higher density than fresh water and is home to fishes like dolphins and sharks.

Freshwater is mainly found in streams, lakes, and groundwater wells. Rainfall is also a source of fresh water. The habitat is home to species like goldfish and catfish. Here are some notable characteristics.

Freshwater Saltwater
Definition Water that contains less than 1% of salt. Water that has a high salt and mineral content.
Density It has low density. It has high density.
Freezing Point 0°C -2°C
Natural sources Ponds, groundwater, streams. Oceans, Seas.
Common fishes found Catfish, goldfish, salmon. Shark, Cod, snapper

Scientific research revealed that saltwater contains 35g of salt per liter. The presence of salt in saltwater makes it have a lower freezing point than fresh water.

Freshwater has a limited supply, housing only 3% of all water bodies. One-third of freshwater is fit for human consumption, while the other part is in the form of polar caps and glaciers. Generally, fishes that live in either salt or freshwater have adaptation techniques that make them fit in.

Important Facts About Goldfish

Below are some amazing facts about goldfish you should know.

Important facts about Goldfish

  • No stomach: The fish has no stomach, and it is advised they are fed with easily digested food. The lack of stomachs makes them produce lots of waste.
  • Goldfish have a memory span of up to 3 months: Goldfish can remember events for up to three months, ranking them among the smartest fishes.
  • They can be huge: The size of their tanks mostly limits goldfish growth. Also, poor water quality in the wild can make them reach up to one foot in length.
  • Goldfishes can survive freezing temperatures: Their body metabolism will slow down, but they can survive even in frozen water for some time.
  • The goldfishes are omnivores: They have a broad diet and can eat anything, including smaller fish.
  • They taste with their lips: Goldfish don’t have tongues. So, they use their lips as the organ for tasting their food.
  • Gain color from sunlight: They cannot produce pigment in the darkness and will turn white. They have unique color combinations and no two goldfish have the same color.
  • Lay a lot of eggs: A female goldfish lays up to 1000 eggs or more at a time. Though some of the eggs don’t get fertilized or get eaten by predators, a lot survive and increase their population.
  • The fishes  can overfeed: Without a stomach, the fish can easily keep eating without knowing when it has overfed. This is quite dangerous and can lead to death. They should be fed not too regularly but in measured portions.
  • They have a lot of varieties: There are more than 300 known species of goldfish with distinct color patterns. The diversity was mainly caused by cross-breeding.
  • Their eyes can see UV and Infrared: Their sight is better than that of humans at seeing colors. They can see a combination of four different colors when compared to the three (red, yellow, and blue) the human eye can see.
  • They can survive for a long time without food: Goldfishes can hibernate. As such, they can easily go for an extended period without food. They can store fat and use it when there is a food shortage.

Watch this YouTube video to learn more exciting facts about goldfish:

Bottom Line

Freshwater and saltwater fishes adapt to their unique surroundings. Freshwater is the natural habitat of a goldfish. So, putting a goldfish in saltwater could lead to death from the collapse of their cell structure.

If you wish to set up a fish tank for goldfish, it’s essential to take note of key factors. These are salinity and pH levels. Also, a clean environment with good water is the best place to raise a goldfish. Although there are rare cases where goldfish survived in saltwater, subjecting them to such is torture

Hi, this is your friend Clifton Ervin, the founder and chief editor of this site, Aquariumwolf. I completed my graduation in marine biology and became an Ichthyologist. One of my favorite hobbies is aquarium keeping; therefore, I love to talk about fish keeping, breeding, food behavior, etc., and much more relevant to aquarium maintenance. I have created this site Aquariumwolf, to share my 20 years+ of experience and knowledge with all new to this journey.

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