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Changing Goldfish Water 101: 6 Easy Steps

Changing the water in your goldfish's tank is likely a chore you put off as long as possible. Water changes may be an annoyance.

It can be tedious and dirty, and when you get up the following morning, goldfish poop will be everywhere again.

Yet, there are a few tips and tactics that make it easier to change the water in your goldfish tank.

Let's talk water changes in "Changing Goldfish Water 101: 6 Easy Steps" by BestForPets (bestforpets.org)!

Why Bother Doing Water Changes?


You have an effective filtering system, so why do water changes? Yet, a decent filtering system can only do so much. Ammonia and nitrite will be neutralized by adequate filtering and converted to nitrate. But, it will not eliminate nitrate from your aquarium.

As a fertilizer, plants absorb nitrate, but they often do not remove all of it from the tank. Water modifications assist in eliminating excess nitrate. Not to mention that water changes allow you to vacuum the substrate or tank bottom, as well as clean around decorations and other locations where waste accumulates!

Poor water quality is one of the most prevalent causes of sickness in goldfish. Regular water changes can help you maintain the best environment possible for your goldfish.

This can help prevent infections and create a hostile habitat for parasites and other pests. If you do not undertake frequent water changes, your fish may be susceptible to disease.

Equipment Needed for Performing Water Changes

  1. Gravel vacuum/siphon (nano and small tanks)
  2. Python or another mechanism for water change (medium and larger tanks)
  3. Pail for soiled water
  4. receptacle for pure water (used distilled water bottles work well)
  5. Water treatment
  6. Water test kit

The 6 Steps for Goldfish Nano and Small Tank Water Changes are:

1. Shut it down

Switch off the tank’s heater, filter, and any electrical components. Disconnect everything to prevent water from dripping into an outlet. If you neglect to switch off your water heater before draining the water, the unit might explode. If you neglect to turn off your filter before draining water, the motor might be damaged.

2. Vacuum/siphon

Create suction with the gravel vacuum. Either use the hand pump that is built into the tube or place the end of the gravel vacuum in the tank, flip it upside down, and fill it with water until suction is generated.

Be sure to vacuum crevices, the substrate, and around aquarium decorations. Consider the sections of your tank where the most waste may gather and concentrate your vacuuming efforts there.

3. Prepare purified water

If desired, step 1 and step 2 can be executed in a different order. Add the water conditioner to your clean water container. Before adding the clean water to the tank, allowing the water conditioner to rest in the clean water enables it to neutralize or eliminate contaminants.

Your water conditioner should eliminate chlorine and chloramines, and neutralizing ammonia and nitrite is a plus but not a must.

4. Toss the old water

When your clean water is resting with the water conditioner in it, you may throw your old water. The water from a fish tank may be utilized as plant food, thrown outside, or poured into your sink or bathtub.

If you opt to discharge the water outside, you must check that it contains no invasive plants, animals, or pests. This contains duckweed, parrot’s feather, hornwort, a few species of fish and snails, and a variety of other commonly found objects in home aquariums.

5. Add pure water

At this time, you may begin putting clean water back to your tank. To prevent accidently shocking your fish, you should ensure that the temperature of the clean water is similar to that of the tank water. Carefully pour the clean water into the tank, taking care not to frighten the fish or disturb the plants or décor.

6. Restart

After adding clean water to the tank, you may reconnect your devices and restart everything. Verify that your water level is sufficient for your filter to function and that it at least reaches the “fill line” on your heater. If the water level remains too low, repeat steps 3 and 5 again.

The 6 Steps for Goldfish Medium and Larger Tank Water Changes are:

1. Turn it off

Switch off and disconnect any tank electronics as described previously.

2. Connect the tubing

Connect the tubing to a nearby sink according to the directions for your Python or water-changing system. This may necessitate removing the sink’s filter. Please note that these systems are not compatible with all faucets. The likelihood of finding a faucet that fits your kitchen sink is high, but it is not guaranteed.

3. Siphon the water

Place the siphon end of the water changing system into the tank, set the tubing to “drain,” and then activate the sink to which the tubing is connected. This will provide suction, allowing you to remove contaminated water from the tank and deposit it directly into the sink. If you have little fish or other creatures that may be pulled into the tube, you should not use this procedure.

Without connecting the tube to your faucet and manually creating suction with a hand pump, then dumping the unclean tank water into a bucket, as instructed for nano and small tank water changes, is an alternate way. This will let you to inspect your filthy water before dumping it, ensuring that no fry, tiny fish, or invertebrates have made their way into it.

4. Turn off the faucet

If you connected the tubing to the faucet, then you must switch off the sink after withdrawing the water. This will halt the suction, preventing water from leaving the tank.

5. Condition the tank

Treat your tank immediately with the water conditioner, following the instructions for the amount of water you will be putting to the tank. If you withdrew 30 gallons of water from a 75-gallon tank, you must treat the tank for 30 gallons of new water before refilling it.

6. Refill and relaunch

If you’re utilizing the way in which your water-changing system is connected to the sink’s faucet, then you may switch it to “fill” and reactivate the sink. Ensure that the end of the tube is in the tank before proceeding! Once the tank has been filled to the desired level, turn off the sink, remove the siphon, and reconnect and power on your devices.

If you manually siphoned instead of using the faucet, you can proceed with steps 3-6 from the nano and small tank water changes.

Now What?

After doing a water change and let the aquarium to settle, you should use the test kit to examine the water parameters. This will let you to confirm that ammonia and nitrite are absent, nitrate is at a safe level, and pH is within the acceptable range.

If you are having trouble regulating water parameters following a water change, examine the parameters of the water you are re-adding to your aquarium. Tap water is more likely to contain chlorine and other chemical compounds that are toxic to fish.

Now that you know how to change the water in your fish tank properly as described in “Changing Goldfish Water 101: 6 Easy Steps” by BestForPets (bestforpets.org), it is time to get your fish a clean home.

Author Image

Dr. Deborah Fletcher

Deborah R. Fletcher, DVM, is a skilled veterinarian with more than 15 years of experience dealing with companion and exotic animals. She has experience caring for a variety of animals, including household cats and dogs, reptiles, birds of prey, and even primates. Dr. Fletcher is a valuable part of the BestForPets team, where she contributes to their aim of providing pets and their owners with the finest possible treatment and services.

Veterinarian (DVM) Dr. Deborah Fletcher


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