If you are considering getting a Goldfish, you are probably already aware that fish have surprisingly complex needs. Not understanding a fish’s requirements can have serious consequences, and may result in your fish getting sick or even dying.
With that in mind, we’re going to cover some of the basics you’ll need to know about your Goldfish’s water requirements. If you’re just using plain tap water in your Goldfish bowl, you are going to have a very unhappy fish very quickly!
Let’s start by finding out about what kind of water Goldfish need, and what you should do to make sure your fish stays happy and healthy.
What Kind Of Water Do Goldfish Need?
Goldfish are resilient, and will tolerate a fairly wide range of environments. They prefer a temperature range between 62 and 72 degrees F, and they must be kept in freshwater. They prefer a pH value between 7.0 and 7.3, but they will tolerate up to 7.5 if your water is more alkaline.
They like hard water, preferably around 120ppm, but they will tolerate softer water. The water must not contain any salt, but these fish do need calcium and magnesium to survive, which is why hard water is best for them.
With that in mind, let’s look in more detail at the kind of water you should use for your Goldfish.
The most obvious source of water in most homes is the tap – but can you put tap water in your fish tank?
You can keep a Goldfish in tap water provided that you treat it with water conditioner first. Tap water contains chlorine as a disinfectant, and this is dangerous for your Goldfish.
Tap water can contain up to 4 milligrams of chlorine per liter of water. This is considered perfectly safe for humans, but it is far too strong for fish. If you put a Goldfish in standard tap water, it will die quickly.
The chlorine will burn your fish’s lungs and make it impossible for it to breathe. Even if you remove your fish from the water, it may suffer from long-term injuries that will never fully heal.
Furthermore, tap water contains heavy metals, including things like copper, zinc, and lead. They are present in low quantities and not dangerous to humans, but they could kill a fish.
Very small amounts of certain metals may not harm your Goldfish, but exposure to the levels found in tap water is potentially deadly, and must be avoided.
You therefore need to make the tap water safe for your Goldfish – but how do you do this?
How Do You Make Tap Water Safe?
You can get rid of chlorine simply by letting the tap water stand out in a shallow dish for 24 to 48 hours, but you shouldn’t use this method if you want to use the tap water for your Goldfish.
That’s because tap water also contains chloramine. This is similarly harmful to a fish’s lungs, but takes longer to evaporate from the water.
Leaving the water out also won’t combat the heavy metals.
Some people do use this method successfully with their Goldfish, but it isn’t recommended, and it can take a long time, particularly if you have a large aquarium.
Fortunately, you can still use tap water for your Goldfish if you treat the water first. Purchase some water conditioner from your local aquatics store, and use it every time you are going to add water to your fish’s container.
It’s important to make sure you are purchasing the correct conditioner, however. Some only tackle chlorine. You need one that will deal with chlorine, chloramine, and heavy metals.
Follow the instructions on the bottle for mixing the conditioner with tap water, making sure you adhere to the recommended quantities. This will ensure that the tap water is properly treated and made safe for your Goldfish. Different conditioners will require different methods, so stick with the manufacturer’s guidelines.
You can see a basic guide on conditioning tap water here.
Can You Top Up The Aquarium With Untreated Tap Water?
You shouldn’t add any untreated tap water to the aquarium, even if you are only doing a partial water change. The risk will be lower, because the tap water will be diluted, but you should still avoid this.
You could hurt your fish by changing even 10 or 20 percent of its water for plain tap water. Always condition the water before you add it to your aquarium.
Can You Wash Tank Components In Tap Water?
You might be wondering whether it’s safe to rinse the tank’s components down with tap water when you’re cleaning the aquarium out. After all, the fish won’t come into direct contact with things like the filter sponge, so will the chlorine matter?
It is not recommended that you wash any parts of the tank in plain tap water. This is because they will be home to good bacteria that is keeping your tank balanced and dealing with the ammonia.
The chlorine in the tap water will kill these bacteria, and the tank’s ammonia levels will increase sharply. This will put your fish at risk.
You should therefore always wash tank components in your existing tank water. This will allow you to get rid of any buildup and dirt on the filter, without disrupting the bacteria that are so important to your fish.
If you’ve got bottled water from the store, that might seem like an excellent replacement for tap water. However, some kinds of bottled water also contain chlorine, so you should be careful about adding this to your tank.
You can leave bottled water out or treat it with water conditioner and then use it, and this will work. Bottled water has useful minerals and a neutral pH value, so it is a viable option.
The drawback is that bottled water can be expensive, even if you purchase it in bulk online. Many people therefore prefer to stick with conditioned tap water.
Distilled water may sound like a good option because it has had all of its impurities removed. It is created by boiling water, collecting the steam, and condensing it back into water. That might sound like a great idea for your fish, but it has some drawbacks.
Goldfish are used to swimming in mineral-rich waters, and as mentioned earlier, they need to get calcium and magnesium from their environment. When you distill water, you remove the minerals that the fish are depending on, and cut off their access to these nutrients that they need.
However, you can use distilled water to top up your fish tank if its level is low. Adding a small amount of distilled water won’t be harmful because there are minerals in the rest of the water.
You don’t want to be filling most of the aquarium with distilled water, but a small amount won’t be problematic.
If you do need to make some distilled water to top up your tank, you can do this yourself at home. There is a video here that will show you how.
You can also add a mineralizing buffer that will replace the lost minerals. This will let you use distilled water for the aquarium if you choose to – but bear in mind that this is more complicated than using treated tap water.
Purified water has been processed to remove heavy metals, bacteria, pollutants, and viruses, so it might seem like a great option for your Goldfish. However, you should be a little cautious, because the term can refer to quite a few different things.
Distilled water, for example, is a type of purified water, and we’ve already seen that it can be problematic for a Goldfish. It’s therefore important to understand what purification process was used.
You may wish to get water testing kits if you plan to use purified water for your Goldfish bowl. These will give you more information about what is and isn’t in the water, making it easier to tell whether it would be suitable for your Goldfish or not.
Having water testing kits handy and regularly testing your water conditions is a great habit for people who keep fish, because this is one of the best ways to ensure that your tank is always right for your fish.
How Often Does A Goldfish Need Fresh Water?
- You should aim to partially change your Goldfish’s water once per week. This reduces the risk of ammonia and nitrite spikes, and ensures that the tank stays clean and hospitable for your fish.
- About a quarter of the water should be changed. You can take this opportunity to perform some cleaning as well. Start by turning off the filter and air pump, and then use a siphon to remove dirt and waste from the tank. This will also remove water. Don’t remove more than a third of the tank water.
- You can see how to properly clean a Goldfish aquarium here. As you can see, the tank filter should only be washed in your current aquarium water, and not in tap water.
- Adding some nitrifying bacteria after you have finished cleaning your Goldfish aquarium can help to replenish any beneficial bacteria that have been disturbed by the cleaning process. This ensures your tank stays healthy.
Goldfish are hardy and will tolerate a reasonably wide range of water conditions, although they do prefer hard water and a neutral pH value. They cannot be kept in salt water.
You can keep a Goldfish in tap water provided it is suitably treated first, using a suitable water conditioner that will remove chlorine, chloramine, and heavy metals.
You can use bottled water or purified water if you prefer but it’s important to test your water parameters regularly to ensure your fish has access to all the minerals it needs.