Will Cloudy Water From Sand Hurt Fish?

Last Updated on December 6, 2021 by cmoarz

So you’ve finally decided to add sand to your aquarium. A nice step up from artificial gravels! But once you added it, everything get’s super cloudy? Is it always going to be like this? Will cloudy water from sand hurt my fish?

These questions will be answered in this article as well as what will happen to your fish and how you can clean the cloudy sand up to make it crystal clear.

Is Cloudy Water Bad for Fish

Will cloudy water from sand hurt your fish? Yes, it certainly can. While it likely won’t kill them outright, you definitely don’t want your fish in such an environment.

That cloudy fog you see when adding new sand to a water-filled aquarium is actually small particles of sand and dust that need time to settle out of the water column.

That dust can get stuck in fish’s gills, irritate their eyes and various other issues can crop up from such a particle-filled environment. This can even lead to various forms of impaction and infections that could end up killing your fish. Some fish are even more sensitive than others.

How to Fix Cloudy Water From Sand

You have 4 solid options to remove sand from a water column.

Option 1: You can do a fish tank water change. If you have a cloudy fish tank, the best thing you can do is try and get as much of that debris out as you can, and a water change is a perfect medium to do that.

You may need to do several water changes to notice a big difference.

Option 2: Use a filter. Filters media will remove sand particles very quickly, especially if they are loaded up with filter floss which can easily catch the smaller particles of dust.

The downside to this option is your filter will be very dirty and it may cause issues with the cycling of the tank for a couple of days. You will most likely need to rinse out your filter a couple of times during this process.

Option 3: Using a bio-magnet water clarifier product. These products are designed to pull particles out of the water column and help them settle at the bottom quicker.

In fact, Most bags of sand you purchase for aquarium use will have a small package of clarifier included buried in the sand. So when you are rinsing your sand, be sure to look out for that and remove it first!

Many people don’t feel comfortable using this option as the clarifier is technically a chemical. But it remains an option, and one that’s much better suited when there are no fish already in the aquarium.

This is the clarifier I recommend if you need to purchase one. API ACCU-CLEAR Water clarifier.

Option 4: Just wait. If you don’t have any fish in the aquarium you need to worry about it. Just let the sand settle out naturally, which should only take a day or so.

Avoiding It In The First Place

A cloudy fish tank from sand is actually really easy to avoid. When possible sand should be put in first before water is added to the aquarium. Use a piece of plastic with slits cut in it to stop the water from agitating the sand as you pour it into the aquarium.

A cut 2-liter soda bottle is good for this. Simply remove the top and cut small slits or holes into the sides and bottom. This should allow the water to fill the aquarium without disturbing the sand too much.

Before you place the sand in, you should also give it several washes in clean water. Keep doing it until the wash water runs clear. No matter how much you wash your sand, you will always get some debris and cloudiness, though.

If you intend on adding sand to an already established aquarium, there are things you can do to minimize the clouding.

First, wash your sand really well to get rid of the bulk of the light floating particles. This will make a big difference.

Fill a small container, such as a Tupperware container, up with the sand. Dunk the entire container into the aquarium gently and allow it and the sand to slowly fill up with water.

Lower the container close to the bottom and gently dump the sand where you want it to go.

While this process is slightly more time-consuming, It’s possible to get sand into an aquarium with live fish and not have to worry about clouding everything up with sand particles.

The real trick is to make sure the sand moves as little as possible during the pouring. This avoids dust kicking up into the water column.

Can I Add Fish to Cloudy Sand Water

It’s not recommended to add fish to cloudy sand water. It’s bad for the fish in various ways and they defiantly won’t enjoy it. It’s always better to have a tank set up, cycled and ready to go before adding new fish.

If you absolutely need to add fish as soon as possible, use a water clarifier. It will work its magic within an hour and make the water safe for your fish. Double-check the instructions on the back of the clarifier you’ve purchased as they aren’t all made equally.

How to Prepare Sand for Aquarium

Do an initial search of the sand to make sure there’s no glass or large rocks. If there are any, remove them. (Get a reputable brand if you don’t want to worry about this).

Dump sand into a bucket and remove the packet of clarifier that came with it (if it had one). Rinse the sand while sifting it with your hands with normal tap water.

Dump the dirty water while keeping the rest of the sand on the bucket, and repeat the process several times until the water runs clear.

Sand will never be completely clean. It’s sand after all. It’s like sweeping a dirt floor. But the majority of the loose particles will be removed during the rinsing process making it much better later on.


Owner of AquariumGravel.com and also owner of actual Aquarium Gravel believe it or not! ;). Setting up beautiful aquarium sceneries and habitats since I was very young. Enjoy!