fish tank water change

Goldfish Tank Water Changes

Having goldfish is awesome.


They swim around in their tanks, all happy as if they don't have a care in the world. Of course, for the most part, they don't.

As long as they are cared for properly anyway. 

They don't have any bills to pay, they don't have to hunt for their own food and they don't have to dispose of their own waste. What better life could a fish ask for?

Gold fish tanks need regular water changes to stay healthy.

Why? Because unlike ordinary tropical fish, goldfish put off a LOT of waste. And that waste turns to ammonia which is deadly in even slightly medium amounts.

So water changes help keep the levels down to a safe level that is not harmful.

Now the question is, how do you change the water correctly?

air bubbles in water

The answer is easier to explain sections instead of one really, really long answer.

Below, you will find out what you need to change the water, how often you should change it and how much as well as what NOT to do when changing the water.

What you need to do to change.

There are a few options when it comes to doing a water change in your tank. Pet supply stores carry a variety of tools that can make this job much easier.

However, some of the products are unnecessary, and can be costly at that. 

All you really need to do a full or even a partial water change is either two buckets, a smaller one and a larger one, or a bucket and an aquarium vacuum.

An aquarium vacuum is a siphon that you can get fairly cheap at any pet supply store.

Genuine TERA PUMP Aquarium Cleaner Aquarium Fish Tank Gravel Sand Cleaner with Long Nozzle N Water Flow Controller - BPA Free (model: TRFTCLN)

When it is time to do a change, you may need to remove your fish from the tank.

If you only have a few fish this step may be unnecessary, but if you have a lot, you may want to take them out and set them in a large container with water from their tank. 

This is for their safety as goldfish tend to be very curious and may swim in your way.

It can also be a little less stressful for them if you put them back after you have cleaned and refilled the tank.

Once you are ready, take some newspaper or towels and lay on the floor in front of your tank to catch drips.

towels orange and yellow

Stick the suction end of your vacuum hose (if you are using one) into the gravel in your tank.

Whether it is automatic or manual, start the vacuum. If you are using buckets, stick one into the water and proceed to scoop out as much dirty water as you can. Dump it into the larger bucket. 

Remove the correct amount of water based on the type of change you are doing and the size of your tank.

How often to change and how much.

This can depend on the tank size and amount of fish you have. The recommended is no more than 2 fish per 20 gallons.

At that size, a once a week partial change, at least one-third of the water, is perfect for keeping the tank clean.

change 1/3 of water weekly

Once a month you can do a larger change, between half to two-thirds of the water.

Even if you do the larger changes once a month, it is recommended to do the partial changes weekly.

Changing the water in your tank does not have to be a difficult chore.

As time goes by, you will learn little tricks and techniques that make the job much easier for you. 

These can be just about anything and will depend on the size of your tank, how many fish you have, what else is in the tank, the location of the tank in your home or business, and the ease of access to the tank.

What NOT to do.

Never completely empty the tank out UNLESS it is absolutely necessary.

fish bowl

Beneficial bacteria take a long time to set up and when you empty the entire tank, you destroy that bacteria.

However, there are times that a full, complete water change and tank cleaning must be done.

1. Your fish were sick. For instance, your fish got ick. Once you have cared for the fish, you will need to completely change out the tank and wash it. This will helps prevent them from getting sick again. It is not a guarantee that they won't, however, if you do not change and clean the tank, it is almost a guarantee they WILL get sick again.

goldfish black smudge

2. Water changes are not reducing the ammonia levels enough and your fish are getting sick or dying. In this situation, it is best to remove all of the water and clean everything. However, it is very helpful to use the dirty water from the tank to clean instead of fresh water. This will keep from removing all of the beneficial bacteria that are needed in a healthy tank. (Hint: If this is a recurring problem, you may have too many fish in your tank or not enough filtration for the tank size or amount of fish. Try reducing the fish and adding more filtration to reduce the pollution.)

swim bladder disease

What else NOT to do.

  • 1. Don't forget to condition the water before adding it to the tank.
  • 2. Don't pour to fast. You can shock the fish and beneficial bacteria with a fast changing temperature and the high pressure. Pour the water into the tank slowly.
  • 3. Don't stir up the bottom of the tank. While it seems this would get more of the bad stuff from the tank, in actuality, it only makes a tank cloudy and disturbs the beneficial bacteria. Use the aquarium vacuum to remove debris from the bottom.

Now that you have the basics of cleaning your goldfish tank, you can feel confident that you are doing it right.

Your fish will thank you and you will thank yourself if you clean it regularly. After a while, the smell of a dirty tank is awful.

 While you may not notice it, your company probably will. Besides, your fish will live much longer and healthier lives in a clean tank.