Introduction: Turn Your Old CRT Computer Monitor Into a Fish Tank ! ! !

Picture of Turn Your Old CRT Computer Monitor Into a Fish Tank ! ! !

Talk about a great screen saver! I've been wanting to do this build for a while now. Just about every time I see and old CRT computer monitor by the side of the road on trash day I think to myself ...that would sure make a cool looking fish tank. So here is my first attempt at turning and old computer monitor into a fish tank.

Step 1: Gather Your Materials.

Picture of Gather Your Materials.

An old CRT (Cathode Ray Tube) computer monitor
Plexiglas (I use 1/8 inch)
Two part epoxy
Clear bathroom/kitchen grade silicone caulk
Paint for the background of the tank
Duck Tape
Hot Glue
Permanent markers
Expanding insulation foam

Safety glasses or face shield
Thick work gloves
Utility knife
Rotary tool with cutting bit
Speed square
Measuring tape
etc. ...whatever works

Step 2: Removing the CRT

Picture of Removing the CRT

I began by removing the old speakers attached to the side of the monitor by unscrewing two bolts on each side. I then promptly plugged then into my ipod. They worked great giving me amplified music to work by.

Next I removed four screws that held together the plastic housing, opened it up, and removed the monitors guts...very interesting stuff. The Cathode Ray Tube its self was attached to the very front of the plastic housing with four more metal screws that I, of course, removed (make sure you save all the mounting screws as you will need them later).

Step 3: Keeping the Curve.

Picture of Keeping the Curve.

WARNING - the Cathode Ray Tube is in vacuum. Breaking the tube can be VERY DANGEROUS. If you are to attempt this please be sure to wear proper safety gear (eye protection/face shield, gloves, etc.).

When I began this I was really hoping to be able to simply cut/drill a hole in the top part of the CRT, clean out the inside, caulk the back where the cathode is, and then fill it with water. BOY WAS I WRONG. Long story short, there is a big metal screen inside the CRT and I cracked the glass beyond repair, but who knows maybe I will try again sometime now that I have gotten a better look at the inside of the CRT.

Luckily, after my failed attempt at putting a fairly large hole in the CRT, the front of the tube was still not cracked. So it was up to me and Mr. hammer to get rid of the excess glass.

Once the excess glass has been removed you will need to remove the metal screen. Do not use a grinder to do this like I did. There are metal studs that go through the glass and using a grinder will cause the metal to expand and then the glass to crack. The metal screen can be removed by pressing down and over on the screen support clips.

Now that the metal screen is out the screen needs to be cleaned. I used some WD40 and an old t-shirt rag and it seemed to do the trick. Be careful the stuff on the screen flakes off a lot and is probably not very good to breath in, so wear a mask and turn your shop-vac on to catch as much of the flake/dust as possible.

Next I went a head and put some duct tape around the edge of the glass to soften the edge and keep it from biting me.

Step 4: Plexiglas Is Your Friend.

Picture of Plexiglas Is Your Friend.

Okay, so I decided to use the front of the glass CRT as the front of the fish tank and make the rest out of Plexiglas. Begin by measuring, measuring, and some more measuring. See what will fit inside your monitor (Chances are that you will change these as you build, but you need to start somewhere right?).

When cutting Plexi you can score it deeply with a utility knife and then snap of the pieces. On the other hand, if you are fortunate enough to have a band saw, you can just measure, mark, and cut. In my experience, using other saws require a special blade otherwise the Plexi will splinter or crack. Anywho, measure, and cut out you pieces, then lay them out I use some small pieces of duct tape and taped them together to see what it was going to look like. Remember, the front of you tank will be curved so the front of your Plexi should also have a curve to it. Try as best you can to match the curve of the glass. Once I had all the Plaxi pieces cut and ready, I layed all the pieces flat, mixed up a batch of two part epoxy for plastics, and glued the three sides and the bottom together using a little duct tape to hold them in place while the glue set up.

Step 5: Painting a Background.

Picture of Painting a Background.

I did not want to look at the dull gray plastic of the inside of a computer monitor, so the next step I did was to paint on the OUTSIDE of the Plexi fish tank. I began by taking a silver Sharpy permanent marker and a speed square and I drew out some circuit board lines (again on the outside). I then to a green Sharpy to add some shadows under those lines. Finally I masked off the edges and spray painted the OUTSIDE with some cheap green spray paint (of course you could paint whatever you would like to).

Step 6: Access Panel.

Picture of Access Panel.

To make the access panel I used a rotary tool with cutting bit and carefully cut along the top edge of the top of the tank. This allowed it to be secured by slipping the, already present, tabs under the front part of the plastic monitor housing.

Step 7: Attaching Plastic to Glass.

Picture of Attaching Plastic to Glass.

After many test fits, I went ahead and mixed up a batch of two part multipurpose epoxy, spread it on the front edges of the plastic tank, as well as on the glass front, and then maneuvered the tank into place. I then put a few pieces of scrap wood inside to push against the plastic in order to bow the edges. This effectively curved the edges out to the edges of the monitor and then let it cure. While the epoxy was setting up I added some hot glue around the outside of the tank in an effort to fill gaps and to create a better fit.

Step 8: Fill-er-up!

Picture of Fill-er-up!

I felt it wise at this point to test fill the tank. Good thing too because it leaked! So now what? Well I first tried hot glue.... It still leaked. Then, after searching my workshop, I found a partial tube of clear bathroom/kitchen grade silicone caulk. This seemed to do the trick, of course if you happen to have a tube of aquarium sealant that would probably work better. After a few more test fills and leak checks the tank was ready to be returned to the monitor housing.

Step 9: Lighting.

Picture of Lighting.

For lighting I picked up a small fluorescent bulb that fits into a regular light bulb socket. Also, after searching the basement I found an old heat lamp that I could use for the fixture. To keep the light bulb from falling in the water I cut a small piece of 2 inch PVC pipe, cut a groove in it for the lights switch to fit, sanded one side, and then used some super glue to glue it to the underside of the access panel. The power cord for the light goes out the back of the computer just like the monitor power cord normally would. The tube for the bubbler worked in much the same way, with the tube coming out the back.

Step 10: Water Support.

Picture of Water Support.

Begin by returning the tank to the monitor housing and securing it with the screws you originally removed. Next make sure your lighting and air lines are in place. At this time it would be a good idea to fill the rest of the computer housing outside the tank with expanding insulation foam. When it cures this will not only insulate your new tank, but more importantly, it will support the weight of the water that the Plexi is attempting to contain. My concern here is that if there is no support under the plastic tank it may rip away from the glass front.

Step 11: Finishing Up

Picture of Finishing Up

Fill your new tank up with water, add gravel, rocks, fish, etc., plug in and enjoy.

Extension ideas:

Make a clear plastic hood to keep any water from splashing up to the light.

Connect the light switch to the on button on the monitor.


Josh28 (author)2014-06-12

great idea but the crt is made of leaded glass and that stuff you were cleaning off was probably phosphorus. Plexiglass is definitely the way to go for both your health and your fishes :-)

LauraK14 (author)Josh282015-10-13

I thought exactly the same-that fish prob didn't last long!! poor thing...not to mention that tank isn't suitable for a goldfish...goldfish are DIRTY because they poop ALOT and need large quantities of water and excellent filtration! with an external filter perhaps a tetra or two in this, without only suitable for a betta....(and you don't use a bubbler with a betta...)

StephanieR3 (author)2015-01-28

I've actually been planning on doing a planted (maybe aquascaped) tank in an old monitor for an art project at my university!

However, unfortunately this fish won't survive long in this small of an environment. If you had a way to filter and heat it, it appears to be probably 3-5 gallons and could hold a betta or possibly a small school of something like white cloud minnows (maybe?). You could even use it to breed gorgeous cherry shrimp and make some good cash selling their babies! But goldfish get extremely large and have no stomachs (meaning they don't digest food well and foul your water very very quickly) so they need big tanks with lots and lots of filtration. That's why they don't live as long in bowls (they can live to be 20-30 years in tanks and ponds, sometimes even more!). I have one fish that is the same as this little guy and her body is the size of a softball and her tail alone is almost a foot long! Not trying to judge, just trying to spare you and your adorable little girl the heartache of losing a pet. Been there, done that, learned my lesson! They're very easy to care for once you have the equipment. If you could find a way for it to hold the weight, a larger television might be able to hold a cool tropical community or maybe even your goldfish if it's at least 30 gallons. That would be super awesome!

agulesin (author)2014-12-28

Nice project!

Can you add a Warning about smashing CRTs near the start of the article, something like this:

"Wrap the CRT in a heavy blanket to prevent glass shards from flying when you smash the tube. Be careful when unwrapping it afterwards as glass can be embedded in the blanket"

Also might be useful to add a note about breaking the pip off the back of the tube, I've never heard that before.

Better be safe than sorry! :-))

bradster (author)2009-05-29

what about cleaning the fishes water?

Grey_Wolfe (author)bradster2009-05-31

The open port he made in the top of the monitor allows for cleaning. Can use a vacuum pump to pull most of the water out of the tank for heavy cleanings. Only in the case of a full tank failure or a bad case of Ick does one need to drain all of the water, so no worries. One suggestion I would make on this part is actually to spray the outside of the tank Plexiglas with a lubricant that wouldn't damage the paint before putting the foam around it. This would allow for the tank to be slid out the front of the foam after it set, just in case more major maintenance is required.

a.steidl (author)Grey_Wolfe2014-07-21

I'd use plastic sheeting around the tank, before the foam, instead of lubricant. Finding a lube that wouldn't damage the paint might be a little tricky, or expensive. Plastic, safe for sure, and cheap.

jrandlesome (author)2014-02-27

you need to discharge the cathode ray tube or you could get a shok of over 3000 volts

steliospc (author)2013-11-17

VISOR monitor recycling

steliospc (author)2013-11-17

build mame EMACHINES 770 DESKTOP PC PENTIUM 4 WINDOWS XP INCLUDES RESTORE DISCS 570 & 770 Chicony Electronics KB-2961 Wired Keyboard Samsung 3 Button Optical Mouse PS/2 - NEW (X7-01) monitor parckard bell speakers parcard bell

CreativeGeek (author)2013-07-31

Actually, that would be a good idea for a wasp enclosure too.

wertyduke905 (author)2012-06-22

How do you feed or clean the fish tank? Do you have to unscrew it and take out the tank each time? Or is their a Hole in the top?

Michaelthedestoyer (author)2010-05-29

Could the same be applied to a small Television?

or a big television? i found a 52" Sony on the street and it was *'*FREE!!!*'* because it had 2 busted circuit boards, so lucky me :3

mason0190 (author)mason01902012-03-31

And I would assume so, because it's essentially the same thing on a larger scale. It would certainly be more of an ambitious project, though.

mason0190 (author)2011-03-20

Would this work with one of those gargantuan 56" Sony flatscreens? I have one in my garage (free at a garage sale because two circuit boards were fried) and was waiting for a project like this.

ryandean98 (author)mason01902011-06-14

You could actually do that! THere are actually very thin aquariums out there! Check this out:,or.r_gc.r_pw.&biw=1440&bih=813&ie=UTF-8&tbm=shop&cid=7490070703706333955&sa=X&ei=ViP4TeSaNYfEgAfJtKSkDA&ved=0CFQQ8wIwAA

mason0190 (author)ryandean982012-03-31

I meant one of the old-school CRT ones that took up about two refrigerators'-worth of space.

Lol, that'd look so cool. Heh, but I don't think using a flat screen television would work too well (Too thin). Unless it's a chunky one, with the big tube in the back like old school  TVs, then theres possibilities.....

But I think I'd rather buy/swap out the new cirucit boards and have a big flippin' TV. But thats just me...

DIYandSIMPLIFY.Blogspot (author)2012-03-05

hahah - very nice project, my man.

Fail whale (author)2012-01-05

:-p this looks like a great, i havent tried it yet but im gonna try to

SIRJAMES09 (author)2011-10-02

if you build the whole thing out of Plexiglas, what do you need the inner workings of the monitor for?
can't you just build a tank that fits inside the "outside parts" & call it a day?

Keep in mind I would have no idea on how to build this had I not seen your instructable...

I like the way you explained everything, it was easy for me to follow & looks really awesome!!

Ickletas (author)2011-09-21

Great build. The only modification I would make would be to put in underwater L.E.D's for the lighting, this would mean you could fill up top the top of the "screen"

cclark-1 (author)2011-08-13

Awesome project! Didn't Pee Wee Herman have an old box style TV that was a fish tank on his Saturday morning show? If so, I have been coveting it ever since. I have an old CRT monitor that I'm going to start taking apart today and next pay day, hit up the pet store for the silicone and such.

As for the disposal of the dangerous parts, you may actually want to to check with your local Best Buy or we have a store around here that people donate computer pieces so that kids can learn computer repair skills. I'm sure they would have a recycling area for that.

Nxtfari (author)2010-03-03

Where did you dispose of the CRT?

Goodhart (author)Nxtfari2010-04-05

It CAN be a tricky thing.   You could ask your local TV repairman, & he'll "make it safe for disposal" for you,  or you could just take a pair of pliers and break of the tiny knub at the very back of the tube. There will be an inrush of some air,  it is a vacuum after all, and then it won't implode anymore, and the trash man should have no trouble taking it then.   YMMV,  so consult local laws, and someone for safety tips on how to disable the tube for safe disposal.

red9er (author)Goodhart2011-08-05

Although that is good advice, there is also toxic chemicals in CRT's (mercury?) and so you have to take them to a recycling center if u wish to be environmentally responsible.

Goodhart (author)red9er2011-08-05

Yes, you're right, still it is best to "disable" thier implosive nature so the center will accept it.

Goodhart (author)Goodhart2011-08-06

IIRC it is mostly LEAD, but that is still a toxic metal....

rangkale (author)2011-08-01

great!!! love this :)

brennacs (author)2009-02-27

nice instructable :) i always wanted thought about doing something like this. so i know this is random, but is that a cf that screws into a standard light socket? i've been looking for one this shape for a project i'm working on and cant find one anywhere.... :(

JonBoy470 (author)brennacs2011-07-24

IKEA sells bulbs that shape... 11W, 600Lumen IIRC

anpelleg (author)2011-06-02

What brand of dremil is that? mine is a lot bigger and not as nice

tinker234 (author)2011-05-30

nice be funnny to print the windows desktop and lamate love fish there cute just have to get my cat away

Floyd_Droid (author)2009-08-05

Lets be honest... This is an extreme waste of time, money and effort. If you take the amount of money spent + put a price of time it took to create it... you could have bought a very nice aquarium.

If one still feels compelled to build something like this I would suggest NOT to use the CRT and building the tank directly inside the monitor shell with plexiglass. So that your not risking injury breaking the CRT cleanup and so forth.

But most importantly is to consider that most fish are very sensitive to chemical contamination: WD40, Glass Cleaners etc... not to mention the phosphor and gases + God-knows-what-else. Unless you want to have a tankfull of goldfish and black mollies... go right ahead. Marine fish would not survive in such conditions.

You could say that fish keeping in general is a waste of time money and effort. Not to mention natural resources since in order to keep your fish humanely, you should be doing large weekly water changes.

unless your aquarium is extremely overstocked, and tiny anything more than 20 percent every other week is extremely stressful for the fish

It's obvious to anyone that read the article that you skimmed it because there is an instructable about safely disassembling a CRT monitor. They evidently not used the CRT because the surface is flat. Flat screen monitors use lenslike glass and a flat sheet of glass to do it. That means the fish would look distorted. There is a screen inside every CRT to ceep the electron beam from spreading out too much and/or go off center. So you can't put the fish inside the CRT because shadow masks have miniscule holes in the sheet. Aperture grilles, wich have better picture, have wires instead of miniscule holes, so the water will leak a lot faster. My grandma's CRT monitor has controls on the front, so I can put those controls on the fish tank. They are not simply a menu button, there is contrast, brightness, input format and power as physical switches to put in the tank, so I can turn it into a very nice aquarium. The menu will be an easy feeder where the food will come out of the "electron guns" made of brass. There is my message for you.

1spartan95 (author)Floyd_Droid2011-01-28

You have no DIY in you at all. Get off of the internet. NOW!

Jack A Lopez (author)Floyd_Droid2010-02-12

Yikes!  Chemical contamination!? 

Does that mean the goldfish isn't safe to eat? 

thats not the point.

Nxtfari (author)poolshark1620062010-02-12

Of course it is. Why else would you build it.

santy22 (author)Floyd_Droid2009-09-11

But it looks cool!

nerfinaticRN7 (author)2011-01-29

LCD or any flat-panel moniter would be too thin to be made int0 a fish tank, but they CAN be made in2 an ant farm lol. The CRT moniter i'm planning to use has contrast, brightness, power button (definitly) and menu control. I'll try to incorporate those buttons into the fish tank with the menu button being the filter and oxygen input levels.

A VeiwPanel VP150 (a late 90s lcd monitor) is 3 inches thick, thin enough to eliminate the biggest fish varieties. That monitor i'm planning to use is a Nokia Multigraph 446xpro

nerfinaticRN7 (author)2011-01-25

There is a big metal screen because all CRTs have holes to fire a cathode through. Invar shadow masks have miniscule holes, slot masks have vertical rectangles and aperture grills have a sereis of wires to fire through. Why would they fire through holes in the first place? Because a cathode, like a flashlight, gets wider as it gets further away from the source. The holes make the beams narrower.

QueenQuill (author)2010-02-22

 Damn you!  I had this idea many years ago, and always wanted to do it.  Then I saw the Instructabled "Dead PC" contest and thought that now would be the time to do it!  But have to go and do it first!  *cries*  Ah well, I'll still probably build one, because I've wanted one since I first thought of doing it so many years ago!  BTW, good job in the Instructable!

Cobalt59 (author)QueenQuill2011-01-23

Calm yourself.........

Homemadeslop (author)QueenQuill2010-12-07

Many have contemplated using crt tv's and monitors for fish tank I thought of this idea years ago with a funny tv show took an old piano and turned that back part into a fishtank or a fishtank holder of sorts. I havent done it cause I know a little to much about electronics including these chunky tvs/monitors. If you still want to do it, then do it you will be the one that uses a bigger or smaller screen, you can customize it as you wish to make it "your own". Just be careful, do outside with a mask might be a better idea than being in the house due to dusts and all.

faithisroo (author)QueenQuill2010-02-22

yup....i saw that contest too, and wanna make one...but...i guess it's yours...

nice one btw...

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