When you’re ready to get your new aquarium ready, one of the things most talked about is the substrate or aquarium gravel.
Aquarium gravel is a lovely way to not only add aesthetics, but it’s a much-needed medium to help planted tanks thrive, certain species of fish stay healthy, and more.
So, finding the best aquarium gravel is vital for the health and looks of your tank.
Best Aquarium Gravel Quick-Find Table
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Why Use aquarium Gravel in Your Fish Tank?
When people look at aquariums, they may or may not notice the sand or gravel substrate in there.
If they do, most likely, folks tend to just think of it as an aesthetic aspect of the aquarium rather than a functional part of a healthy aquarium setup.
But there are several reasons substrate is beneficial and not just pretty.
aquarium gravel helps with Biological Filtration
First and foremost, substrate provides your aquarium with a natural functional form of biological filtration.
The gravel provides your aquarium with a place for the good bacteria to grow.
Author note: These good colonies of bacteria then helps to eliminate the waste products of fish like leftover food, biological waste, and plant debris. Gravel provides a sufficient area for the bacteria grow.
Live Plants need aquarium gravel
If you’re keeping live plants at all, you’ll want to keep some substrate in your aquarium.
Top tip: The right substrate allows the plants to root properly, which means they’ll grow well and have a healthy life.
aquarium gravel helps Healthy Fish
The right substrate – nothing too bold or bright – helps provide your fish with a healthy habitat. The substrate gives a natural feel to the aquarium for fish and helps reduce their stress.
It also provides a safe place for them to lay eggs, since the eggs can drop down into the crevices between gravel pieces where they’re protected from predators.
aquarium gravel offers Aesthetic Appeal
Finally, there is something simply appealing about substrate.
The right fish tank gravel colors pop in the aquarium while giving the fish tank a healthy bottom and contrast compared to the “open water” feel of the rest of the tank.
It helps to hide debris and helps show off what you do want to see – like a silver-colored fish against a dark substrate versus clear water without a bottom.
When Do You Not Want aquarium gravel or substrate?
While most aquariums setups do well with substrate, a few instances are better off without.
Grow tanks are the primary situations when substrate isn’t that useful. Grow tanks must be kept incredibly clean and require regular water changes and immediate removal of waste and uneaten food. Substrate makes all of this difficult.
Top tip: Hospital and quarantine tanks are the other situations where you don’t want substrate, for much the seam reasons.
Is aquarium Gravel Better than Sand?
Gravel is better for many aquarium situations, though not always the absolute best choice for everything.
Generally speaking, a clean gravel or substrate is usually the best option for freshwater aquarium gravel.
Gravel is usually large enough that water can flow through the crevices between pieces, which means that less bacteria – the bad bacteria, that is – can build up between cleanings.
Sometimes sand is the better option, though. Specifically, sand makes the most sense in certain kinds of saltwater aquariums.
For one, it looks more natural than colored gravel pieces. Secondly, closely packed substrate sand doesn’t need cleaning as often as gravel does.
And food particles rest on top of sand instead of sinking down between pieces like it does with gravel.
Author note: There are some species-specific arguments for both, as well, so be sure to study such things related to your fish and plants. For example, goldfish will become ill if they eat sand and cichlids do better with eating a little sand.
Types of Aquarium Gravel
There are a variety of types of gravel to consider as well, which will suit certain plants and fish better.
Unsuitable Gravels and Sands
Before we look at the good options, I’d like to point out some popular options that shouldn’t be used.
They’re unsafe and unhealthy because they’re untreated for suitable use in your aquarium, will throw off the pH, et cetera, but also can carry diseases and organisms that can kill your fish.
What are these?
Basically, anything you find outside yourself.
Sand you scoop up at the beach, rocks and seashells you find while beachcombing or fishing at the river, et cetera.
Please only use gravel and sand that has been thoroughly treated and sterilized.
Now, onto the good types.
Aquarium Gravel and River Rocks
Ordinary aquarium gravel is probably the most used substrate around. It comes in the form of river rocks, small pebbles, painted rocks – use with caution – et cetera.
This type of substrate is good for fish only aquariums and the top layer of planted aquariums.
Treated Aquarium Sand
As mentioned, certain fish and plants do better with sand instead of gravel.
We’re reviewing gravel in this article, but there are some great options for aquarium sand as well.
A great option for stabilizing and enhancing pH is crushed coral. It’s typically mixed with aragonite or similar calcium rich materials.
They’re suitable for marine, reef, brackish water, and cichlids tanks.
This porous weathered clay is a great option for use as the lower layer in planted aquariums as it provides nutrients to plants without releasing minerals into the water.
How to Choose What Type of Gravel
There are a few considerations to keep in mind as you choose your gravel.
What Type of Tank Do You Keep?
The first – and most – important thing to consider in your aquarium substrate is the type of tank you keep.
Fish only, reef tank, marine aquarium, planted, breeder, et cetera all have different needs.
The species of fish also have different needs, as mentioned above with cichlids and goldfish as examples.
Some quick thoughts on this include:
- Fish that enjoy burrowing do well with sand substrate
- Planted aquariums need clay substrate to thrive
- Goldfish should not have sand
- Some cichlids prefer sand
- Marbles or large pebbles do well for breeder tanks
- Some cichlids do better with harder alkaline water which can be obtained with the help of crushed coral
What Color Gravel is Best for Fish Tanks?
Many experts believe that the color and type of substrate used should be as close to the natural environment of the fish and plants you keep as possible.
Most fish, however, are adaptable and will do fine with pink, red, blue, or yellow gravel, assuming they are well-cared for.
Author note: The color is primarily going to be about your preferences over anything else. Just be sure to avoid badly dyed sand or gravel that can chip and make your fish ill.
How Much Substrate Do You Need?
The general rule with substrate is that it should be between 1.5 and 2-inches deep at the bottom of your tank.
This can change due to the type of plants you keep, though, if the plants have a robust root system.
Verify these depths before going any thicker than the suggested maximum of two-inches, however, as too deep a bottom can cause anaerobic zones that are problematic for fish.
Reviews of the Best Aquarium Gravel
Thinking through the best fish tank gravel ideas, you’ll easily find great options based on the criteria above.
But to make the process a little easier, we’ve dug around through many reviews and found the best of the best aquarium gravel with the highest ratings with solid reasons behind their ratings.
The CFKJ Large River Rocks make a great additional to any aquarium where you need some larger decorative stones. The rocks are usually about 1 to 2-inches in length.
The stones are natural aquarium gravel river rocks that have been polished and sterilized properly for a smooth, beautiful look and high-quality, non-pH affecting substrate for your aquarium.
These beautiful stones come in a variety of light to dark stones that add an incredible aesthetic to your freshwater tanks while providing a top-layer of gravel for the fish and plants that do well with large stones.
These are particularly good for goldfish tanks – they can’t really eat these stones! – and koi ponds.
The stones are all natural, smoothly polished, fade-resistant stones at a reasonable price.
Our Verdict on the CFJK Large River Rock Gravel
If you need large river rocks, you’ll love these.
They’re beautifully and smooth, easy to position, great for fish that tend to get sick from eating small aquarium gravel and add a gorgeous warmth to freshwater aquariums that smaller gravel just can’t add.
Overall, this is one of the most gorgeous substrates you’ll find for your freshwater aquarium.
If you’re looking for that fine aquarium gravel substrate level to help your planted aquarium flourish, you’ve found it in Seachem’s Flourite Black Clay Gravel.
I’ve been familiar with this substrate for years and basically only ever seen good things from it.
While it’s designed for planted aquariums, you can use this beneficial substrate in any freshwater fish tank. The gravel adds a nutrient-rich layer that helps plants root in well.
And while typically this sort of substrate is used with other gravels, it can be used alone, if in the right fish tank.
Seachem Flourite isn’t chemically coated or treated, so it never affects the pH of the water, and as long as you clean it properly, you’ll never have to replace it.
Our Verdict on the Seachem Flourite Black Clay Gravel
The only issue I’ve ever seen with this aquarium gravel is the amount of cleaning it requires before installation in the aquarium.
You’ll need to rinse it several times, most likely, but once it’s clean, you’re good for life.
The substrate settles nicely into the aquarium for a stunning, dark bottom layer that allows plants to happily root in and grow well. It works great with other layers of gravel or by itself, which is also a bonus.
All-in-all, this is the best gravel for planted aquariums.
For those looking for high buffering capacity, Carib Sea is your go-to-choice.
It’s a high-quality crushed coral blended with aragonite that provides over 25 times the buffering capacity of other tropical fish tank gravel.
The coral is Geo-Mraine Florida coral that’s not actually crushed but screened to size to provide naturally formed particles of coral mixed with the aragonite for the perfect substrate.
The blend of aragonite and small coral bits is perfect for high water flow through the bed for under gravel filtration or reverse flow beds.
The grain size is variable between 20 millimeters and 550 millimeters for a more natural texture and look.
The blend is crushed oyster shells with the coral bits and not suitable for burrowing and sand-sifting creatures. It’s great for cichlid tanks and designed with them in mind.
Our Verdict on the Carib Sea Crushed Coral
There are two potential issues with this, though they’re common to pretty much all substrate options.
1. There’s loads of dust, so it takes a fair bit of cleaning to get the substrate aquarium ready.
2. The substrate is a dry mix, to it takes several weeks of cycling for the beneficial bacteria to fully colonize.
Apart from those standard issues with substrate, this is a great option for cichlid tanks in particular. It’s attractive and very natural looking and offers 25 times the buffering capacity of other substrates.
We think this is probably your best bet for cichlids tanks.
I’m not personally a fan of colored gravel, as sometimes the paint can chip, but the GloFish gravel is a unique exception. The pea gravel aquarium size makes it perfect for top layers in planted aquariums.
The bright colors add a vibrant pop of color to the bottom of your tank, while providing a layer of substrate that helps the tank filter out the rubbish left by fish. The variety of colors offered includes:
- Fluorescent pink, green, blue aquarium gravel
- Black with colored highlights
- Black and fluorescent white
- Fluorescent green
- Fluorescent pink
- Solid black aquarium gravel
- Solid white aquarium gravel
It’s important to note that these are painted rocks using safe fluorescent paints that match the GloFish concept.
The colors glow in the bottom of your tank, adding a truly unique and fun aesthetic that you won’t find with other colored gravel or substrate.
The gravel doesn’t affect pH, but the rocks are fairly small and should not be used for aquariums with gravel eating fish because of the paint.
Our Verdict on the GloFish Aquarium Gravel Fluorescent
This gravel is safe for most fish, doesn’t cause water changes in the pH balance, et cetera, and is generally easy to keep clean after the initial rinsing before installing it in your tank.
Be careful which bag you select on the Amazon site. I’ve seen several complaints that people got bags mostly black, when they were expecting bright, fluorescent colors.
This could be a shipping or ordering error, so verify your choice before hitting that purchase button.
Beyond this minor issue, it was also noted that it’s difficult to get clean the begin with. This is fairly standard for most gravels, however, so just have some patience.
All-in-all, it’s a great option for adding some solid fun to your aquarium.
The Best Way to Clean Aquarium Gravel
When you buy your new aquarium gravel, you’ll need to do a thorough cleaning job of it before installing.
However, throughout the time you keep your aquarium, you’ll also need to keep it clean for the health of your fish and aquarium plants. Here’s a quick how-to on that.
- Fill a bucket halfway with dirty aquarium water. Fill the rest of the bucket with clean tap water.
- Put your fish in this blended temporary environment.
- Unplug all your aquarium equipment and siphon out the water from the tank with a gravel vacuum.
- Remove two cups of gravel from the tank and set aside to maintain the bacteria colony.
- Remove the rest of the gravel into two buckets.
- Blast the first bucket with clean water, vigorously stirring the gravel. Repeat the process until the water runs off clear.
- Repeat the process with the second bucket of gravel.
- Clean the rest of the tank and equipment before replacing the gravel, equipment, two set aside cups of gravel, et cetera, and returning the fish to their home.
Species That Do Best with Aquarium Gravel Over Sand
Obviously, there are some stipulations, but there are certain species that do better with gravel instead of sand.
For example, really messy fish are going to do better with gravel instead of sand because, well, let’s be honest – gravel is better for messy fish.
Some fish also eat sand, which is a terrible idea for their health. Cichlids and goldfish, for example, sometimes scoop up sand while they’re trying to get their food.
Sand in the digestive tract can, in turn, cause some pretty serious issues for this fish – intestinal blockages, for example – and can die from the complications.
When in doubt, go with gravel over sand for freshwater fish, unless you’ve got burrower species. In that case, check into which tankmates they can share a sandy bottom with.
Do avoid using crushed coral in most cases, as well, as many species of fish will be harmed by the sometimes-jagged edges of the coral.
Any time you have bottom dwellers, check into their native habitat style before choosing your substrate.
Corydoras, for example, actually do great with smooth pebble or gravel substrate but cannot handle coral.
On the other hand, many cichlids thrive with coral substrate.
It really is a case-by-case situation that you’ll need to look into for each species you stock in your tank.