Introduction: Lava Rock Aquarium Background

Picture of Lava Rock Aquarium Background

In this instructable i will show you how to make a cheap, and easy aquarium background. I use it in my 10 gallon nano saltwater tank, but you could easily make it to fit even the largest aquariums. Infact, i might even make one to fit my 55 gallon.

Step 1: Tools & Materials

Picture of Tools & Materials

1 Utility knife
or 1 circular/jig saw with a carbonfiber blade, or copper cutting blade
1 tape mesure
1 5 gallon bucket
2 towels
1 flat working surface
1 sun
1 greese pencil
1 builders or drywall square
1 peice heavy (40-60 grit) sand paper

1 Sheet of plexiglass 1/8-1/4" thick
1 tube Aquarium Safe silicon. (very important)
1 bag of lava rock

I already had the plexiglass, but i estimate the cost of the materials at under 15$.

Step 2: Measure & Cutting

Picture of Measure & Cutting


Use your tape measure to figure the Inside dimensions of your aquarium. You will want it to be long enough so it can anchor itself in your substrate. Using your grease pencil, mark out the dimensions on the plexiglass using the two existing sides, so you only have to cut two times.

Use your builders/drywall square to acheive a straight cut with the utility knife. Press relitivly hard to get a nice, deep score in the plexiglass.
Once it is scored, position the score line (the score line being up) on the end of a table, counter, or work mate. With one strong movement, press down on the end that is hanging off of the table to achieve a clean break. Repeat with other score and proceed

Step 3: Measuring Some More

Picture of Measuring Some More

As you can see, in my aquarium, i am using an Under Gravel Filtrations system. That leaves me with two uplift tubes, and two powerheads that are very close to the back of the tank. I will not be able to place lavarock in these spaces. Other obstructions can be the uplift tubes of a hang on back filter, or heaters. (if you have no obstructions skip this step.)

Using your grease pencil, mark out where these obstructions will be, and remember not to silicon rocks in these spaces.

Step 4: Cleaning Your Rock & Plexiglass Prepping

Picture of Cleaning Your Rock & Plexiglass Prepping

Chances are there will be dirt, and quite possibly even mud, so you will need to wash your rocks extremely well.

Take your five gallon bucket, and fill it halfway with lavarock. Take your hose out to the street and fill your bucket. Churn the contents with your hand while still filling the bucket, letting all of the muck overflow. Empty the water and repeat. You will have to do it many times. Rinse untill you think the water is clear, and then rinse it three more times. You cant be too careful.

Spread your towels out in the sun on a flat surface in the sun, and spread your rock out amoung the towels. Every 15 minutes, turn the rocks around so they dry. (the silicone will not adhere to wet surfaces)

Now to prep your plexiglass. You want to rough up the side with your heavy grit sand paper to make the silicon adhere better. The sanding creates more surface area to bind to, and gives the silicon a place to anchor itself for a better hold. Dont overdo it, you want to sand in all directions, and have many distinguishable "channels" for the silicon to grab on to.

Step 5: The Boring Part

Picture of The Boring Part

Now sit down at a table, grab a coke/water/beer/bag of human blood, and get comfortable, cause your in it for the long haul. You want to apply the rocks on at a time with a dime-nickel sized dab of silcon and apply it to the sanded side. Get creative, use the wierd looking rocks, use different colors sizes and depths to make it your own.

Step 6: Fin!

Picture of Fin!

Insert it into your tank, and anchor it in the back into the substrate, step back, and admire your work. Heres a picture of the finsihed tank, and Shamus, the yellow tailed damsel (i didnt name him, my girlfriend did...her word is law *cracks whip*)


Smokingdragon (author)2012-12-26

You don't need to use aquarium Silicon and you can use any materials you like.Metal,aluminum,Lava Rock etc. Just know how to seal it making it waterproof and Know you water source,Your fish previous water source. and balance filtration.
Even I'm not into salt water fish Still all are the same.
Good luck with your fish.

DoubleM (author)2011-01-13

hey,could you please tell me ,what's the small grass called?

bassmonkey (author)2009-06-12

if you wanna laugh your eyes, brain, lungs andheart out,

T3h_Muffinator (author)2007-04-16

Pretty cool man!

I aim to please

I aim to kill.... or bake muffins, which ever comes first...

Bake me muffins! NOW!!!

Hahahahahaha I really need to make a muffins instructable! That'd be EPIC!

Tobita (author)T3h_Muffinator2008-11-30

my favorite muffins are lemon with pine nuts and plain eggs flour baking powder sugar oil eggs milk and water *toothy smile*


nepheron (author)2007-06-03

i see

Sgt.Waffles (author)nepheron2007-06-03

Said the blind man to his deaf wife.

dombeef (author)Sgt.Waffles2008-11-15


Guppy8 (author)2008-10-24

Lava rock is terrible for saltwater aquariums. I am a reefer, and lava rock will cause hard metals to leach into the tank. The project is cool, but it will prevent you from keeping inverts and corals. It is also a very bad bacteria culturer. It is porous, but those holes quickly get clogged with ditritus and other stuff.

cybersunset (author)2008-08-11

Great Instructable...will try this with my tank. Thanks!

Mojo_JoJo (author)2007-10-24

Interesting idea, here is something else that can be done but much simpler, 1. Make the size of the plexi glass equal to the internal dimensions of the rear of the fish tank. 2. Slide the plexi glass into the tank and leave about half an inch from the back of the tank. 3. place stones in the cavity between the plexi glass and the tank rear. This might not look as natural as your's though...

whitefish (author)2007-08-31


nepheron (author)2007-06-03

omg, LOL

nepheron (author)2007-06-03


Sgt.Waffles (author)nepheron2007-06-03


nepheron (author)2007-06-03

im sorry, i occasionally change the water in the aquarium (its sealed, only plants)<br/>the Christmas bulb has moss growing....i have other biospheres a bit larger as well.<br/>go here......self supporting?<br/><a rel="nofollow" href=""></a><br/>

Sgt.Waffles (author)nepheron2007-06-03

Still not self supporting. You have to put it in the light so the plants can photosyntizes. Thats about as close as you can possibly get though.

nepheron (author)2007-06-02 like the chalenge of a small tank..(im sure if done harder things, like the 3 inch cross bow working replica, a tiny "ecosystem" in a Christmas light -i only water it once in a while- ,a 1 inch X 1inch self supporting fresh water aquarium...ect...) i may get a crab or small bottom feeder...those nemo fish are fish none the less lol, kidding "clown fish"

Sgt.Waffles (author)nepheron2007-06-02

I almost exploded wsith the "nemo" comment. What is your "ecosystem in a christmas bulb" consist of?. no aquarium is self supporting. Sorry. You still have to add evaporated water. What is in your aquarium, as it is only .02 liters. no fish, or shrimp, or crab can live in such an aquarium. I, personally, would start with a ten gallon. .5 gallons isnt much to work with, and you cant put in any fish, and only one or two corals.

nepheron (author)2007-06-02

hes a nice guy....but odd lol i don't want a ten gallon i like little things easire to deal with i hate fish.

Sgt.Waffles (author)nepheron2007-06-02

If you dont have fish, you will need to clean the tank WAY better, because there is no one to clean up. You could even have a clown fish (but for the love of god, dont call him "a nemo") Even a 10 gallon would be easier to deal with than a .54 gallon.

nepheron (author)2007-06-02

thank u so much!!! i will have to do this sometime (all the stuff i can get is at a semi local aquarium shop) this will be fun when i get the money (i'm a lampworker, meaning i make glass beads!BIG $$!) is it at all odd for an aquarium shop to cure rocks for u? i have no idea how to heat up a can with a rock in 80 degrees is there a method? the story behind my wanting for an aquarium like this: i've always likes animals and plants, and 1 day got seriously intrested in a 10 gallon fresh water aquarium. when i got to the store, i noticed that he (shop owner) had mostly salt water fish. on his desk he had a super tiny aqarium with a super tiny reef in it. i wanted. so i asked what it would cost and what i needed...ect.....ect.... he pretty much said that it was an IMPOSSIBLY HOPELESS task for one of my age, "leave it to the experts" sort of way. im like omg i had no idea that saltwater tank were so hard to set up!! so i asked my mom..... N-O...... i ended up getting the dumbest tank in the world, without fish, i hate fish. i do like shrimp and crabs so i had a crab and three ghost shrimp. :( crab died cause hes saltwater and shrimps are boring. i hate fish. except clown fish cause they are funny. i do like corrals and anemones.

Sgt.Waffles (author)nepheron2007-06-02

Most LFS will carry cured live rock. Also, your light will probobly heat your tank for you. I think that it would be very cool to do a super nano, but i am working on yet another nano reef tank (this is the sixth one since i started). They have small snails and shrimp that would be perfect for a super nano. My my calculations, that is just over half a gallon (.54 to be exact). If you need any help, let me know. BTW, the guy at the fish store sounds like an ass hat. If you want to step it up to do a ten gallon tank, i could help you do that, and really for cheap too.

nepheron (author)2007-05-30

i agree..... it is freekin expensive (where do they get it?lol). tho i can get it 8 bucks a pound :P

Sgt.Waffles (author)nepheron2007-05-30

Is it fiji? That what i get. Lots of cocepods for my damsel to eat, lots of pretty coriline algae, and little sponges and corals too. I just bought another 2lbs today, because its in a cool shape.

nepheron (author)Sgt.Waffles2007-05-31

i have no idea where its from, but next time i see the dealer ill ask. I'm not that much of an aquarium guy and i don't even have a tank right now (they all died, accept the shrimp), but i have a question: it it possible to keep just a little piece of living rock in a salt water aquarium? without adding a whole environment? i think it would be cool just to grow the coral and anemones :)

Sgt.Waffles (author)nepheron2007-05-31

What do you mean without adding the whole enviornment?

nepheron (author)Sgt.Waffles2007-05-31

i heard that u can not have a salt water tank without introducing the animals in slowly, make an ecosystem. like say u got 1 fish that depends on another certain fish, so u cant just have 1 species of fish in a saltwater tank.

Sgt.Waffles (author)nepheron2007-05-31

Completly fals. Totaly and completely false, although that is possible to do though. How big of a tank are you wanting, i can help you out a bit.

nepheron (author)Sgt.Waffles2007-06-01

yes!!! i hoped it would be wrong, i just want a little tank. like 5' x5' x5' (inch). i know its possible cause ive seen 1 this size before. IT WAS SO COOL (he had fish it, ill pass tho) I WANT IT lol also: do u know how long it takes for stuff to start growing(?) , the tank he keeps the rocks in is pretty desolate (or does he switch them?) . ps, if there isnt any fish inside (only what spouts out of the rocks, MABIE one of those cute "sexy shrimp") than do i clean it often?

Sgt.Waffles (author)nepheron2007-06-01

Alright, lets get started.

Ive seen the 5x5x5 tanks before, and thats what we call a "super nano". My 10 gallon is a "nano". You do understand that with ever gallon decrease in water volume, the difficulty of keeping it increases exponentially, right?

The rock is probobly not cured, or "cooked". ask for some cured rock, and if he doesnt have any you will have to cure your own. Here is a website:

Also, you will need a substrate. And without a filter (besides the LR), you will need live sand. Not NEAR as expensive as live rock, but it helps to filter your tank.

Also lighting will be an issue. Try to get a bulb that is the 6th one down on this page:,DMUS:2006-27,DMUS:en&um=1&sa=N&start=0

Look to see if it has a K (kelvin) rating. The kelvin is the color temperature. 6700k is pure white, 10000k is slightly blue, and 20000k is ideal.

The best you will find is 6700k, which is what i have on one of my nanos. I have 40 watts on ten gallons and my condylactis anemone and loads of mushroom corals love it. You will need a cheap, and nice looking desklamp with an adjustable head to hold your bulb.

As for corals, i would do ONLY cheap corals at first. Try musroom corals, as they are the easiest, and fairly cheap. I have some that i am ready to propegat (cut in quarters or eights to make new ones), so if you want to buy a couple, pm me.

Feel free to ask any more questions. Any person that i can convert to saltwater is good!

nepheron (author)2007-05-26

i got idea! use LIVING rock instead of lava rock woulnt that rock with all the coral'n'stuff growing???? 0.o

Sgt.Waffles (author)nepheron2007-05-28

Meh, you could, but i call live rock the new oil. 10 bucks a pound here, so i cant just go braking it up. Id rather use it to house all my SPS and such.

Sgt.Waffles (author)2007-04-16

Why thankyou.

LasVegas (author)2007-03-30

Very nice work. Great Instructable!

Sgt.Waffles (author)LasVegas2007-03-30


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