Whether this is first time owning fish or you’ve kept them as pets for years, you’ll know that they require a tank or aquarium. However, you might not realize that the gravel often kept at the bottom of one of these tanks actually does more than just provide aesthetics. Gravel, also known more broadly as substrate, is there to help plants thrive, keep fish healthy and promote bacteria growth and your fish certainly needs some in their tank.
However, if you’re new to the world of fish and aren’t quite sure which substrate to choose, don’t worry! Below we have compiled a buying guide of everything you need to know about the best fish tank gravel, including what to look for when purchasing and whether you should be picking a sand instead. We have even included some of our top picks and the best sellers, so you can get the best gravel out there. Keep reading on below to find out more.
Why Should I Use Gravel In My Fish Tank?
Gravel is a beneficial part of the fish tank for many reasons. Aside from making the fish tank look pretty, contrasting the tone of the water and often adding different colors to really make the tank stand out, substrate is important for the wellbeing of the fish and other organisms living in the tanks.
Firstly, it helps to keep the habitat healthy for your fish. Fish tank gravel that isn’t too bold or bright gives a natural feel to the tank, mimicking the way they would live in the wild. This helps to keep them calm and reduce their stress. The substrate is also an excellent place for them to lay eggs as it protects the eggs from any predators.
Many fish tanks have live plants in them as well as fish, and substrate allows them to grow. The right gravel allows the plants to root properly. Gravel also provides your aquarium with a place for the good bacteria to grow, which helps to eliminate the waste products of fish like leftover food, biological waste and plant debris. Again, this also mimics how fish live in the wild.
Gravel vs. Sand
The gravel vs. sand debate often depends on what type of fish you are keeping and what type of tank you have. Generally speaking, gravel is a better substrate for many of the reasons we mentioned above. It also has much bigger pieces than sand, so the water can flow easily and less bad bacteria will build up.
However, aquarium sand does have some benefits over fish tank gravel. It is packed more closely than gravel and therefore doesn’t need cleaning as much, and food particles are less likely to get trapped underneath like they do in gravel tanks.
In general, freshwater tanks should have gravel substrate and saltwater tanks should have sand substrate. Certain fish, such as goldfish, can become sick if they eat sand so they will need gravel, but other types, such as cichlids, actually should eat a bit of sand.
The Different Types Of Fish Tank Gravel
There are a few different types of substrate for you to choose from. The type you choose will depend on the fish you have and the type of tank or aquarium they are living in.
Aquarium Gravel and River Rocks
This is the most common type of substrate used. Aquarium gravel comes in the form of river rocks, pebbles, painted rocks and more. It is best used in fish only aquariums.
Crushed coral is a good option if you need to stabilize or enhance the pH level of the tank. Crushed coral is good fish tank gravel for marine, reef and brackish water tanks.
Treated Aquarium Sand
As we have mentioned above, some fish do better with sand substrate.
Laterite clay is a good option for planted aquariums. It can be used as the lower layer and provides excellent nutrients for the plants but without releasing the minerals into the water.
Factors To Consider When Choosing Fish Tank Gravel
There are a few things you should look out for when choosing the gravel for your fish, to make sure you buy the right one.
The type of tank that you keep your fish in will heavily sway what type of gravel you need. Fish only, reef tank, marine aquarium, planted, breeder tanks etc all have different needs. For example, breeder tanks will need large pebbles for keeping the eggs safe.
Just like the type of tank you keep, the type of fish you keep will also influence the type of substrate you need. As we mentioned above, fish like goldfish can become sick if they eat sand and will therefore need gravel, whereas others need to eat a little sand and will benefit from sand substrate. There are also some fish who like to burrow and will therefore need sand to do this.
It is often recommended that the gravel color you choose be as close to natural as possible, to replicate a natural environment for your fish. However, fish can do well with other colors of gravel when they are cared for properly. Some owners like to keep their tank aesthetically pleasing by having multicolored gravel, too.
Gravel size is also important and the size you go for will depend on a number of things. For example, if you are breeding fish, larger pebbles are advised because your fish will be able to hide their eggs in between them. Finely packed sand, however, is easier to clean than larger pebbles because less dirt and debris gets stuck between.
If you’re ready to find the right fish tank gravel for your fish, take a look below at the best fish gravels out there. These are all available to you on Amazon.
The Best Fish Tank Gravel — Reviewed
These natural stones from SACKORANGE are lightly polished for a smooth effect and come in a variety of natural colors with shades such as brown, white, black, red and grey. Making the tank look great, these gravel pieces measure around 1 inch each, making them not too small or too big. The water is able to flow smoothly through these rocks, but they are also not so big that they will trap dirt and debris underneath them. With no sharp edges, this 2 lb bag is perfect for many different fish tanks and aquariums.
Seachem Flourite Black is a specially fracted stable porous clay gravel for the natural planted aquarium. Great for plants inside the aquarium, it is also good for any freshwater tank and can be mixed with other gravel, although works fine on it’s own too. It is not chemically coated or treated, thus does not alter the pH of the water and keeps your fish safe. It doesn’t need to be replaced and works well with an under gravel filter, not softening or decomposing to an unsuitable state within your tank.
This Fluval Stratum is made of mineral rich volcanic soil and is designed for stimulating the growth of aquatic plants in freshwater aquariums. Plant roots easily penetrate and spread throughout the substrate, allowing plants to obtain a variety of key, readily available nutrients that will make them flourish. This gravel helps support a neutral to slightly acidic pH, ideal for most plant species and making it also great for species of tropical fish or shrimp normally kept in planted aquariums. This substrate will not discolor water and is also highly beneficial to nitrifying bacteria.
The Carib Sea Eco Complete Planted Black Aquarium Substrate is complete substrate for freshwater planted aquariums. It encourages healthy plant root growth, while also containing major and minor trace elements to nourish aquarium plants. The basaltic volcanic soil which contains iron, calcium, magnesium, potassium, sulfur plus over 25 other elements, helps to prevent algae growth and there are no artificial dyes, paints, or chemical coatings either. This gravel establishes a natural biological balance which makes cycling a new aquarium faster and safer, too.
Spectrastone Shallow Creek gravel is a high quality, polymer coated gravel that is perfect for aquariums. Because it is composed of inert stone, this gravel does affect the pH of the water and is therefore completely safe for your fish and plants you have living in the tank. Great for freshwater environments, it has a non-toxic coating for further safety and to ensure your fish can live a healthy and happy life! The natural colors also replicate what your fish would experience in the wild, giving them a natural and calm environment to live in.
This gravel from Pure Water Pebbles is perfect for freshwater and is naturally decorative. It provides living space for beneficial microbes and anchoring for plants and also helps with the filtering process of the water in your aquarium tank or pond by increasing the surface area available for nitrifying bacteria to colonize. With a 100% acrylic coating, this gravel is non-toxic and will not alter the chemistry of your aquarium water, making it completely safe for your fish and aquatic plants.
A solid and economical performer, this crushed coral from Carib Sea is the only crushed coral with aragonite, which provides up to 25 times the buffering power of other crushed corals, dolomite, or oyster shell. In reality, it’s not actually crushed at all and is a natural product that is screened to size. Great used alone or with other substrate, you can use this in under gravel filtered systems or reverse flow beds. The neutral color of the coral also helps to mimic a wild environment, which helps your fish stay calm.
This gravel from GloFish is designed to accompany other GloFish products and fish, making a cool and aesthetic fish experience! This 5 lb bag of gravel is specially selected to stand out under the blue lighting in your GloFish aquarium, perfect for fish enthusiasts who want something interesting to show off in their home. This gravel can also be used in tanks without GloFish and, available in a variety of colors, is a great way to brighten up your home. Even better, it is safe for your fish and plants.
This Worldwide Imports Bio-Active Live Cichlid Gravel contains live bacteria to quickly stabilize your tank and restore natural organic balance. Designed for cichlid tanks, this gravel immediately removes nitrogenous waste and is therefore safe for your fish and provides them with a healthy environment to live in. The black and white colors provide your fish tank with an aesthetically pleasing design too, yet are neutral enough to keep your fish content and stress-free.
Fish Tank Gravel FAQ’s
How much gravel should I use in my fish tank?
You should usually use around 1.5 to 2 inches of gravel at the bottom of your tank. If you have plants, you will want a deeper bottom so they can be rooted properly, but too much of a gravel layer can lead to anaerobic zones that are problematic for fish.
When should I not use fish tank gravel?
There are some situations in which gravel is not necessary for your fish. For one, grow tanks don’t need substrate. Grow tanks must be kept very clean and substrate can get in the way and be difficult to clean, especially when you are doing it so often. Hospital and quarantine tanks also don’t need gravel. This is also because it can make the tank difficult to keep clean.
There are also types of gravel that you should avoid. These include badly dyed sand or gravel that can chip and make your fish sick. You also shouldn’t use substrate you find outside such as rocks and seashells. Gravel for your fish needs to be thoroughly treated and sterilized.
How often should I clean my fish tank?
Depending on how many fish you have, and how messy they are, most tanks require cleaning about once every two weeks.
There are lots of different gravels out there and picking the right one for your fish tank is important in ensuring your fish lives a long and happy life. With so many uses and benefits, substrate does more than just make your tank look pretty and keeps your fish and the other organisms living in the tank healthy. Always ensure the fish tank gravel you choose is treated and sterilized and don’t forget to regularly clean out your tank!
Check out our other Fish Tank, Food & Accessories posts here:
- Best 20 Gallon Fish Tank Guide
- Best 5 Gallon Fish Tanks Guide
- Best Aquarium Thermometer Guide
- Best Aquarium Vacuums Guide
- Best Aquarium Gravel Cleaners Guide
- Best Water Conditioner For Fish Tank Guide
- Best Aquarium Rock Guide
- Best Aquarium Plants Guide
- Best Fish Tank Decorations Guide
- Best Aquarium Sand Guide
- Best Goldfish Food Guide