Most people put about an inch or two of pea gravel at the bottom of the tank, fill ‘er up and call it quits until their weekly vacuuming.
But I’m going to show you a better way…
Because gravel can be extremely useful – when done right.
When done WRONG?
It can be a huge pain to maintain.
And even a goldfish safety hazard (in more ways than one)!
Good news:
Today I’m going to show you how you can:
- Reduce or even eliminate tedious and time-consuming gravel vacuuming forever
- Prevent toxic waste pockets from forming and poisoning your fish
- Save your goldfish from the danger of getting a piece of gravel stuck in their mouth
- Make a healthier environment for your fish!
… All by the way you set up your goldfish gravel (and the kind of gravel you use).
Do Goldfish Need Gravel?
Aesthetics aside:
I strongly believe that the majority of goldfish tanks should have some kind of a substrate.
(Psst: substrate = what you put at the bottom.)
Goldfish are foraging creatures and the right substrate mimics their natural environment.
The more natural the environment, the happier (and healthier) the fish will be.
I get it:
Bare-bottom tanks may be easy to vacuum…
… But they prevent goldfish from expressing natural foraging behavior.
They also reflect more of a glare from the lights above, which can contribute to stress unless mitigated by using lots of plants.
I used to have ONLY bare-bottom goldfish tanks, but now I will never use them for anything but a hospital/breeding/fry tank.
You will be amazed at the difference when you see your fish happily pecking along the bottom!
Look:
Goldfish kept in captivity can – and do – get bored unless they have interesting things to keep them occupied throughout the day.
Foraging in the substrate is huge for them.
(It’s what they are MADE to do!)
So while gravel might not necessarily be considered a “basic need” (goldfish can live without it)…
… A substrate is definitely an important part of behavior stimulation for them they shouldn’t be deprived of in most cases.
It doesn’t have to be gravel, per se.
Sand also works exceptionally well as a foraging substance.
But the methods I recommend for installing gravel in your aquarium have so many awesome advantages (including allowing for foraging behavior) that you may find you prefer it to anything else.
How to Properly Set Up a Gravel Substrate in Your Goldfish Aquarium
There are 2 really good approaches I recommend for goldfish.
Each have their own set of advantages in addition to those listed above. You just pick what works best for your tank.
Now:
For either method, you should NOT use regular pea-size aquarium gravel.
Why?
Major. Choking. Hazard.
If you own goldfish, you know how they are constantly picking things up from the bottom of the tank, and the grain size of pea gravel is just right to get stuck in their mouths.
This can cause stress, damage or even death to the fish.
Yikes!
Too small = choking hazard.
Too large = nasty debris buildup.
So I recommend only using larger gravel that is 1/2″ to 3/4″ large in size – these ones are perfect.
Tip:
Wash your gravel first to avoid problems with cloudy water after setup.
So let’s get to it!
Method 1: Walstad-Style Gravel Bed
Benefits:
The additional benefits of this method primarily have to do with adding a soil layer below the gravel.
What’s so great about dirt?
According to Diana Walstad, author of Ecology of the Planted Aquarium:
- You can grow bigger, happier plants without expensive fertilizers and cO2/liquid carbon
- Dirt contains bacteria that breaks down ammonia and nitrites – and even nitrates.
- The bacteria in the soil break down the waste that falls through the gravel, preventing toxic hydrogen sulfide pockets from forming which can hurt your fish and greatly reducing maintenance.
- Dirt contains probiotic bacteria to prevent disease in your goldfish
- It helps to prevent pH crash by stabilizing the KH
- And it continually releases important minerals into the water, which means you do not have to change the water to replenish minerals.
It is only recommended to use organic potting mix for your soil layer as you do not want to introduce chemical fertilizers into your aquarium which could harm your fish when submerged.
She recommends using 1″ of dirt underneath your gravel.
The 1″ gravel cap above the dirt prevents the fish from making a huge mess of it in your tank.
(Note: you will need an empty, dry tank to do this.)
- Put down 1″ Organic Potting Mix. You can remove the most obtrusive sticks or bark by hand.
- Add .5″ gravel on top of the dirt
- Plant your live Plants
- Add remaining .5″ gravel
- Fill the tank by slowly pouring water onto a dish or plastic bag
Soon after the soil has been added, it may impart some excess nutrients into the water in the form of ammonia or nitrite.
This does not always happen and will quickly go away, but if it does extra water changes may be needed initially as the soil acclimates to a submerged state.
Remember:
It might take some extra work up front, but in the long-term the maintenance-reducing and cost-saving benefits far outweigh it.
Method 2: Reverse Flow Undergravel Filter
Maybe you don’t want dirt in your tank or don’t want live plants, but want the benefits of gravel’s massive surface area for biological filtraiton?
An undergravel filter might be the solution for you.
But there’s some issues with a standard UG filter setup…
… Because it pulls gunk down between the rocks and can be hard to clean and get rather nasty.
So I recommend reversing the flow to force the waste up through the gravel bed, where the particles can be trapped by intake sponges or another prefilter.
You can read more on how to set this up in my other post.
Read more: How to Set Up an Undergravel Filter
How Much Gravel Do I Need for My Tank?
Look:
The amount of gravel you need depends on how deep you want your substrate.
You can use this calculator to determine how many pounds you’ll need based on the dimensions of your aquarium.
Oh, and don’t forget:
I’ve found it’s better to err on the side of buying a little more, because if you don’t have enough during the setup process it really is a pain to wait to get more 🙁
Final Thoughts
I hope you found this post useful, and maybe even learned something new!
What do you think?
Do you like using gravel in your goldfish tanks?
Have a tip you want to share?
Let me know in the comments below!
Featured image credit: Lawrencekhoo, Wikimedia Commons CC4.0
Ugghhhh so much conflicting info. I currently use Top Fin® Premium Aquarium Gravel in deep blue sea color but I’m moving my fish from a 32g to a 125g and I want to set them up right. I don’t have issues with the gravel… yet. I’m so nervous about them choking but then again, I’m nervous about swim bladder issues by ingesting sand. I have never had any swim bladder issues in any of my fish (knock on wood) and I’m worried if I switch from gravel to sand (many suggest pool filter sand) they may begin to ingest the sand and hence the problems I’ve never had to deal with begin….
Honestly it depends on the size of mouth vs gravel size. Don’t worry about them ingesting sand, that is what they live with in the wild.
How do you clean an aquarium with dirt and gravel? Will the dirt come up through the gravel if u use a gravel vacuum?
Short answer, is you don’t… unless there’s just a crazy amount of mulm buildup, you just do a light surface vacuum.
I am preparing to setup a 55 gal tank and would like to employ the Walstad-Style Gravel Bed. I have some questions please.
1. the organic potting mix is my plant substrate correct? and it is what gives nutrients to the plants right?
2. In #3 when you plant your live plants, are you just setting them on top of the first .5\” and then layering atop the roots with the final .5\” of gravel?
3. So there is no sand involved in Walstad-style gravel bed? could I add sand on top of the last .5\” instead of gravel??
4. If setting up a new tank this way, how long before I can add my goldfish?? — Since the weather is starting to warm up I\’ve noticed some aggression with the goldfish in the pond (it\’s too shallow when it doesn\’t rain) and I\’ve noticed gulping for air (eek!). I am desperate to get them out of the yard pond ASAP!
5. would you recommend, FOR THE SAKE OF TIME, that I set up a sand bottom for starters and get them in there ASAP once it\’s cycled, and then at a later date, when they are safe and out of harms way, setting up the plant filter??
Please help!
1. Yes.
2. I push them in with tweezers into the soil.
3. Some use sand. For larger fish gravel is not so easily moved around.
4. You can add them same day and water change as needed. Or wait until the water tests good.
5. See above.
THANK YOU SO MUCH! I will add then same day and check levels/change water accordingly. So glad to know I can do that. Also, when you say gravel, are you referring to the turtle pebbles or the caribsea sand? Or does it matter? I have both comets and fancy. If I am understanding correctly, it may be better to use the larger pebbles with the larger comets and the caribsea sand, or other finer grain sand, with the smaller fancy goldfish. Would you recommend this??
The organic potting mix is actually much lighter in weight than Eco Complete. I actually bought more than I needed last time I set up a tank with this haha. Gravel refers to the pebbles. The gravel is fine for fancies too. It is just more sturdy to hold up against the slim-bodied fish. I think I used 1.5 big bags I got from the garden center on my 90 gallon tank, if that helps.
Bought your book today. Thank you for that! Looking forward to getting a better grasp on it all. One more question, I am using the following website as a substrate calculator: https://www.plantedtank.net/substratecalculator.html
Using this, would the organic potting soil be essentially the same thing as their \’Eco-complete?\’ I\’m trying to translate potting soil weight to aquarium inches.
Merci beucoup!