How Does Water Temperature Affect the Respiration Rate of Goldfish?

Researched by Nicole Q.


The purpose of this experiment was to determine the respiration rate of goldfish (Carassius auratus) in different temperatures of water.

I became interested in this idea while I was watching a show on Animal Planet that had people asking questions on their pets and one of the questions was what temperature is the best for her goldfish. 

The information gained from this experiment might help people who want to own or who already own goldfish keep them healthy by knowing what temperature is best for their fish.


My hypothesis is that the warmer the water, the more rapid the respiration rate will be.

I base my hypothesis on what a fish expert from Pet Paradise said "the warmer the water the more waste they will produce because their heart beats faster, so their metabolism will work faster."  I think that a faster metabolism will mean a faster respiration rate.

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The constants in this study were: 

  • The same species (goldfish) (Carassius auratus)
  • The same type of habitat (20 gallon fish tank)
  • The same amount of food (2 tiny pinches)
  • The same type of food (Tetra Min Flakes)
  • The same time of feeding (7:00AM & 7:00PM)
  • The same amount of time to count (1 minute)
  • The same pH level of tank water
  • The same amount of fish (12)
  • The same fish (use same fish over again for every test)
  • The same rate of increasing temperature (10 degrees)

The manipulated variable was temperature of the aquarium water.

The responding variable was the respiration rate of the fish. 

To measure the responding variable I plan to count the number of times in one minute that they open and close their mouths and/or their gill covers.

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12 goldfish (Carassius auratus)
2 dividers
1 fish tank (twenty gallons)
20lbs. Rocks (buy at local pet store)
1 pump
1 heater
1 lidful of "pH down"
1 water plant (at least)
1 countdown timer
1 thermometer (that goes a high as 26.7°C & as low as 10.0°C)

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Getting Ready / Housing the Fish

1. Get the 20-gallon aquarium tank and set it in a safe area.
2. Assemble the pump and heater
3. Pour rocks into tank.
4. Put 20 gallons of water into the tank.
5. Add one capful of  "pH Down."  Let the water get acclimated for at least 24 hours.
6. After the water is acclimated and stabilized at 21.1°C. buy the fish (Carassius auratus) and put them into the tank.
7. Feed them a tiny pinch of food twice a day (7:00 AM and 7:00 PM).
8. Give the fish time to get used to their new habitat before beginning the experiment.

Conducting the Experiment

1. This experiment will be conducted at four different Celsius temperatures: 10.0°, 15.6°, 21.1°, and 26.7°.  These temperatures are safe for goldfish according to owners of pet stores that raise goldfish.  The first experimental measurement will start at the lowest temperature, 10.0°.  Use a small amount of ice in a plastic bag to slowly reduce the tank temperature to 10.0°.  Allow the tank to stabilize at this temperature for at least 6 hours.
2. Using plastic tank dividers, calmly and slowly section the aquarium into three zones, with all12 of the fish gently corralled into the center "waiting " section.
3. Carefully and calmly net one fish from the central section and move it into the end of the tank that is the "observation zone".  Wait 5 minutes for the fish to become calm.
4. Using a countdown timer for 60 seconds count the number of respirations of the fish.  A respiration will be one gulping action of the mouth and gill cover.  Record the data.
5. Carefully net the fish again and move it into the third section of the tank where the fish that are "done" with the current test will stay.
6. Repeat steps 3-5 for all remaining fish.
7. Remove the dividers.
8. Slowly increase the tank temperature by 10°.  This will take about 1 day because it must be done slowly. Allow the tank to stabilize at this temperature for at least 6 hours.
9. Repeat steps 2-7 at the new temperature.
10. Repeat steps 8 and 9 at 21.1°C and 26.7°C.

After the Experiment

1. Net all the fish carefully and place into a large plastic container filled with the aquarium water.  Quickly transport the fish to Yakima Tropical Fish and Pet Village, being careful not to let them get too cold.
2. Donate the fish to the store. (They have agreed to accept them.)


The original purpose of this experiment was to determine the respiration rate of goldfish in different temperatures of water.

The results of the experiment were all the fishís respiration rates were very similar. They were unbelievably  accurate and clear.

See the table and graph.


My hypothesis was that the warmer the water the more rapid the respiration rate will be.

The results indicate that this hypothesis should be accepted 

Because of the results of this experiment, I wonder if I had used different temperatures that were spread farther apart what the data would look like? 

If I were to conduct this project again I would have used higher temperatures because 10.0 degrees Celsius is just too low. 

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The food chain is very important to every living creature. If the food chain happened to fall apart, everything could die instantly. Fish are one of the many species that participate in the food chain. If fish were to become extinct humans and billions of other animals would die off also and pretty soon there would be nothing left on the face of the earth. 

The goldfish's ancestors are dull colored carp bred in China and Japan. The goldfish that were placed in bodies of fast flowing water such as rivers and lakes. Soon enough they loose their striking appearance of their ancestors. Along time ago the Chinese bred the goldfish to get new colors, different types of body shapes and sizes, fin shapes and sizes, and tail shapes and sizes. The Japanese helped to create some of the unique and strange fish we see here today. The goldfish was first bred in the in 1878 in the United States. Today there are still goldfish farms in the U.S.

Unlike the land animals, almost every single fish gets their oxygen from the water. There is a certain amount of dissolved oxygen in water. To receive the oxygen the fish have to gulp in through their mouths and pump it over their gills. Most fish have four pairs of gills that are enclosed in a gill chamber located on both sides of their heads. Each gill consists of two rows of filament attached to a gill arch.

Even though there are over 100 breeds of fancy goldfish, although only 20 of those kinds are sold today. Four of those are comet, lionhead, veiltail, and fantail. Another kind is called scaleless because their scales are so light they can barely be seen. Goldfish come in many different colors. Those colors can be red, orange, yellow, gold, white, bronze, gray, black, calico, greenish bronze, purple, lavender, and blue. Some goldfish may only grow 5 to 8 cm (2 to 3 in.) long, and some more than 30 cm (1 ft.) in length.
They can live to be as old as 50 years or older. Wild goldfish usually don't live any older than 15 years and the domestic goldfish that live in homes barely live to be 5 years old. 

 A goldfish is usually known to be in captivity, but they do have a natural habitat. They are found in warm waters. Those waters are located in Southern Canada, United States, and Mexico, although the goldfish originated in China. Lakes, ponds, or sloughs with a soft bottom, a lot of aquatic vegetation, and the warmer water temperature.
 Just because they live in warmer waters, goldfish can tolerate extremely low temperatures and low levels of dissolved oxygen.
 After goldfish have been captured for numerous years they should not be let loose in the wild again.

Compared to most animals goldfish require very little care. A tank with rounded sides such as the fish bowls arenít as good as a tank with strait sides because it gives more room on the surface to allow more air to absorb. The water in the fish tank must have no chlorine and free of any other harmful chemicals. In many cities they use chlorine to purify the tap water. If chlorinated tap water is to sit for 24 hours the chlorine will leave and the goldfish can be carefully put into that fish tank.

The food chain is very important to our lives and the lives of other living beings. Fish are one of the most important animals in the food chain because almost all animals that are meat eaters, eat fish. That's why if they disappear the food chain will be broken and eventually everything would die off.

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Chambers, Kenneth A. "Goldfish" Microsoft Encarta Encyclopedia 2000

Fetzer, Scott. "Fish" The World Book Encyclopedia. 1999. Pp.144-149, 161-163

"Goldfish," Comptonís Interactive Encyclopedia, 1995.

"Goldfish" Grolier Multiple Encyclopedia 1998

Mills, Dick.  "Aquarium Fish" New York, NY: DK Publishing Co.  1993 
Pp. 12-29, 34, 43, 213


 I would like to thank the following people for their help with my science project:

  • The people at Yakima Tropical Fish and Pet Village for loaning the 12 goldfish for me without charging my family and for trusting us with their fish.
  • My dad and mom for buying all the equipment for the fish tank and for making sure I got all of it accurate.
  • Mrs. Hostetler for giving my class and I more time to make everthing perfect and for giving everyone a little help.

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