Putting together an aquarium for tropical fish is a big responsibility. In doing so, you’re essentially determining how safe, healthy, and pleasant your fish’s living environment will be.
Accessories such as filters and thermometers rank highly on the average new aquarium owner’s list, alongside high-quality food and cleaning supplies.
However, there is one particular aquarium component that often doesn’t get the level of consideration it deserves: aquarium gravel.
You’d be forgiven for thinking that gravel only serves aesthetic purposes in aquariums, but that’s actually not the case.
In order to thrive in their aquatic environment, fish need to coexist with beneficial bacteria.
This bacteria is responsible for cleaning the aquarium on a microscopic level, removing fecal waste, food remnants, and other potentially harmful substances before they accumulate to dangerous levels.
Gravel provides a convenient crevice-filled surface for this bacteria to grow and multiply.
We’ve selected and reviewed the best aquarium gravels on the market for your convenience.
Not only will these gravel products look great at the bottom of your tank but they’ll also help to provide the biological filtration that your tropical fish rely on to stay healthy.
Want your aquarium construction to go swimmingly? Here’s our top pick:
- Completely natural
- Polished for smooth edges
- Multipurpose use
- 2 lb bags
- 1-inch stones
Quick List Best Aquarium Gravel
- SACKORANGE 2 LB Aquarium Gravel
- Exotic Pebbles PMS0510 Polished Gravel
- Seachem Flourite Black Clay Gravel
- Spectrastone Shallow Creek Regular
- Oubest Fish Tank Rocks
|Top Top Top
|SACKORANGE 2 LB Aquarium Gravel River Rock - Natural Polished Decorative Gravel, Small Decorative Pebbles, Mixed Color Stones,for Aquariums, Landscaping, Vase Fillers (32-Oz)
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|Seachem Flourite Black Clay Gravel - Stable Porous Natural Planted Aquarium Substrate 15.4 lbs
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|Spectrastone Shallow Creek Regular for Freshwater Aquariums, 5-Pound Bag
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|Oubest Fish Tank Rocks Glow Blue/Glow in The Dark Pebbles for Garden/Fish Tank/Aquarium/Plant Pots/Bonsai Walkway/Driveway 100pcs
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Top Pick: SACKORANGE 2 LB Aquarium Gravel
SACKORANGE’s Aquarium Gravel is one of the most highly reviewed gravel products amongst aquarium owners.
This gravel is composed of natural river rocks that have been polished to ensure smoothness and shine. The lack of sharp edges ensures the comfort and safety of your aquarium’s inhabitants.
All of this gravel’s beautiful, earthy colors are naturally occurring, so you can rest assured that no potentially dangerous chemicals have been added for effect.
The colors do resist fading, however, so you’ll be able to enjoy their natural vibrance for a long time.
This type of gravel also ranks highly on the convenience front due to its multiple potential uses. While this gravel works very well in aquariums, it can also be used in terrariums or for potting bulbs and plants such as cacti.
The only real drawback to this gravel is that it’s on the larger side, with each stone measuring about 1 inch.
This isn’t necessarily a health risk for your fish because larger stones have the benefit of being much more difficult to breathe in or swallow in the first place, but some customers have reported rocks being larger than advertised.
Additionally, for aquariums larger than 10 gallons, you will need to purchase more than 1 of these bags, unless you plan to use this gravel in combination with a different type.
- No sharp edges
- Available in 2 lb bags
- On the larger side
Second Pick: Exotic Pebbles PMS0510 Polished Gravel
This polished gravel from Exotic Pebbles is the perfect, low-key addition to any aquarium.
Each 5 lb bag of this gravel contains a mix of different natural-colored pieces of gravel, each measuring around ⅜ of an inch. This is roughly the pea-like size recommended by most aquarium experts.
The 5 lb quantity of gravel provided in each bag is ideal because each bag provides roughly enough gravel for a 25-gallon tank.
This gravel has been polished to eliminate sharp edges and the risk they present to your fish.
A great feature of this Exotic Pebbles gravel is that it can be used in aquariums and ponds as well as in plant pots, terrariums, and gravel walkways.
In addition to being beautiful and high-quality, this gravel is also very affordable considering the amount of gravel you get per bag.
While most customers have been highly satisfied with this gravel, it’s worth mentioning that several customers have reported a waxy coating on the surfaces of the stones, which may flake off in the water and cause filter clogging in some instances.
- Mixed colors
- No sharp edges
- Ideal size
- Available in 5 lb bags
- Wax-like coating may cause water debris
Third Pick: Seachem Flourite Black Clay Gravel
Seachem’s Flourite Black Clay Gravel is suitable for use in freshwater aquariums. It can be used on its own as recommended, but it may also be mixed with other gravels if necessary.
This is porous clay gravel that is particularly ideal for planted aquariums, both in terms of appearance and pH since the gravel won’t alter the pH of your aquarium.
This gravel is safe for aquarium use because it is not chemically treated or coated.
Additionally, this gravel is actually beneficial for aquarium life, and because it doesn’t disintegrate, it doesn’t need to be replaced.
Each bag contains 15.4 lbs of gravel, which is enough to supply a 75-gallon tank with some to spare.
However, it’s important to note that due to its composition, this gravel requires extremely thorough rinsing before use.
When not rinsed properly, it may turn aquarium water dark and cloudy. In the event that this does happen, though, it should be easily fixable using mechanical filtration.
- No chemical coating or treatment
- Will not alter water pH
- Does not need replacing
- Available in 15.4 lb bags
- Requires extremely thorough rinsing
- Not saltwater compatible
Fourth Pick: Spectrastone Shallow Creek Regular
Spectrastone’s Shallow Creek Regular gravel is a beautiful and safe gravel option for freshwater aquariums.
Available in 5 lb bags, this gravel is perfect for aquariums, plant pots, and terrariums.
The coating that provides this gravel with its high-quality shine is plant-based and non-toxic, so you don’t have to worry about it causing harm to your pets. It won’t affect the pH balance of your water, either.
The recommendation for use of this gravel is slightly higher than average, with the product guidelines stating that 1.5 to 2 lbs of gravel should be used per gallon of water.
This is probably due to the smaller size of the gravel pieces. Therefore, the 5 lb bags should be enough to supply a 10 to 15-gallon aquarium.
- Available in 5 lb bags
- Not saltwater compatible
Final Pick: Oubest Fish Tank Rocks
If you’re looking to add a pop of color to your aquarium, we recommend Oubest’s glow-in-the-dark Fish Tank Rocks.
These gravel pieces work by absorbing light during the day, which they then store up, providing about 2 to 3 hours of glow at night time before fading.
Even without the glow, however, these rocks are brightly colored and will make a beautiful contribution to your fish tank.
Glow-in-the-dark gravel often causes concern amongst aquarium owners due to the potential inclusion of toxic chemicals to achieve this effect.
However, Oubest’s fish tank rocks are completely safe, non-radioactive, and non-toxic.
This gravel is long-lasting and can retain its glow-in-the-dark function for up to 15 years.
As well as looking stunning in aquarium environments, you can put this gravel in plant posts or use it for garden decoration.
Oubest’s fish tank rocks are available in 3 color options, including blue, green, and multi-colored.
However, these rocks should not be stacked on top of one another, so they aren’t appropriate for creating multiple layers at the bottom of your aquarium.
Instead, they are better used as a top layer for another gravel.
Additionally, some customers have reported being disappointed with the level of glow provided, although the majority of customers have been satisfied.
- 3 color options
- Not suitable for layering
- Some customers report insufficient glow
Best Aquarium Gravel Buyers Guide
If you need a little extra help deciding which type of gravel will work best in your tropical aquarium, read on!
Our buyer’s guide lists and details everything you should be aware of prior to purchase.
Tropical fish come in freshwater and saltwater varieties, so depending on what kind of fish you keep, you will either have a fresh or saltwater aquarium.
Because of the risk of disintegration, if gravel is exposed to the wrong type of water, it’s important to verify what kind of aquarium a specific gravel type is compatible with before purchase.
Where a compatible water type has not been stated on the product information, this could either mean that the gravel is universally compatible or only freshwater compatible.
In these situations, we recommend erring on the side of caution and assuming freshwater-only compatibility.
This is because salt water is more likely to disintegrate incompatible gravels than freshwater.
The size of individual pieces of gravel merits careful consideration.
In the past, when aquarium filtration technology was less advanced, gravel size was a bigger issue than it is today because it was much more common for pieces of gravel to get stuck in filter systems, causing blockages or even breakages.
These days, filter technology is such that this is more or less a non-issue.
However, factors such as the type of fish that live in your aquarium can have some bearing on what gravel size you should be using.
In general, we recommend erring on the side of caution and opting for smaller gravel pieces.
This is to ensure that, in the event that a piece of gravel should be swallowed or inhaled by one of your fish, it can easily pass through either the gills or digestive system without causing problems.
Alternatively, if you favor larger stones, you should make sure that the stones are big enough that they can’t be swallowed or inhaled at all.
Unfortunately, many well-meaning fish owners get so caught up in the beautiful color ranges provided by aquarium gravel manufacturers (see below) that they don’t take the issues of chemical composition into account.
However, the sad truth is that artificial colors in gravel can have a negative impact on the health of your fish.
Chemical coatings may leak out into the water in your fish tank, releasing potentially toxic chemicals.
That’s why it’s so important to take note of any artificial chemicals that may be present in your gravel before you introduce it into your fish tank.
We’ve made sure only to include non-toxic, non-radioactive gravels on our list to ensure the optimal health and safety of your pets.
Where a polish or coating has been added for the purposes of edge softening or shine, we’ve also made sure that this coating is either plant-based or at the very least non-toxic and non-pH-altering.
Chemical composition and coatings are an especially important factor to be aware of when purchasing brightly colored or glow-in-the-dark gravel.
These gravels are the most commonly associated with water discoloration, fish sickness, and even death due to harmful chemicals.
This is why we’ve omitted some very popular gravel brands from our list owing to reports of harm caused to aquarium inhabitants following their use.
We’ve left this section until last because, as we’re sure you’ll agree, aesthetics take second place to practicality and safety when it comes to constructing an aquatic environment for fish.
However, we also know that creating a fun, inviting space for your fish to live in and for you to enjoy looking at is important.
As the products reviewed above have demonstrated, aquarium gravel is available on the market in a wide selection of stunning colors that are sure to make your fish tank pop.
Whether you’re hoping to construct a more natural-looking aquatic environment or a striking, brightly colored one that brings out the colors of your tropical fish, you’ll find something in our list of products to meet those requirements.
As we mentioned earlier, glow-in-the-dark and bright gravel colors have a higher risk of toxicity than other types of gravel. However, the colorful options on our list have been verified as non-toxic, non-radioactive, and generally safe for use in the appropriate type of water.
Frequently Asked Questions
Do I need to put gravel in my aquarium?
Gravel isn’t strictly a necessity when it comes to keeping your aquarium’s environment healthy, but it’s much more beneficial than many aquarium owners realize.
As we mentioned in our introduction, the single most important function of aquarium gravel is the facilitation of biological filtration.
By providing a safe and ideal space for healthy bacteria to breed, you increase the amount of biological filtration that can take place in your aquarium.
The result is a cleaner, healthier, and generally safer environment for your fish to thrive in.
There’s also a real benefit to yourself here, in that the more biological filtration takes place, the less you need to physically clean your aquarium, so it’s a win-win situation for both yourself and your fishy friends!
How much gravel should I put in my aquarium?
Exact recommended gravel amounts will, of course, vary significantly according to tank size.
However, there are some general rules and guidelines to follow to ensure that you’re providing your fish with roughly the correct amount of gravel for their biological filtration needs.
A simple and reliable rule of thumb is to add 1 lb of gravel for every gallon of water in your aquarium.
So, for example, if you’re working with a 10-gallon tank, you’ll need approximately 10 lbs of gravel.
If fish are the only residents of your aquarium, the recommendation is that you should have a gravel layer of about 2 inches.
If you also keep live water plants or bottom-feeding creatures in your aquarium (think eels and cory catfish), you should add an extra inch of gravel.
This is to make sure that your plants stay firmly rooted and your bottom-feeders have plenty of depth to scavenge in.
Do I need to change out my aquarium gravel?
Eventually, you will reach a point where the gravel in your aquarium needs to be changed out and replaced for hygiene reasons.
Unfortunately, however, this process isn’t quite as simple as just scooping out all the gravel and replacing it with a fresh layer.
As we discussed above, the primary purpose of aquarium gravel is to provide a place for beneficial bacteria to multiply.
Once your gravel has been in place for a while, a significant amount of this bacteria will (hopefully) have built up.
This means that if you get rid of all your existing gravel at once, you risk seriously upsetting the natural ecosystem of your tank.
This can have serious consequences. In the absence of healthy bacteria, ammonia and other harmful chemicals such as nitrite will build up in your aquarium with nothing to control it.
If these chemicals reach harmful levels, they can effectively poison your fish, leading to sickness and, in some cases, death.
But don’t panic! There are ways you can change the gravel in your aquarium without putting your fish in danger.
Probably the easiest way to change your aquarium gravel without disrupting the overall environment is simply to change out a little at a time.
This way, you’re gradually introducing the new gravel while retaining enough of the bacteria in the old gravel to avoid chemical shifts.
You’ll need to use a divider for this process so that the only and new gravel doesn’t get mixed up, and you’ll also need to time the gravel switches so that it doesn’t coincide with filter cleaning.
This ensures that your aquatic environment remains as stable as possible.