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




About: Church, Family, Work, Play.

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.

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Step 1: 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

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.

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.

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.

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.

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.

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!

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.

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.

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

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.

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    291 Discussions


    5 years ago

    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 :-)

    1 reply

    Reply 3 years ago

    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...)


    4 years ago on Introduction

    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!


    4 years ago on Introduction

    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! :-))


    Reply 10 years ago on Step 10

    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.


    Reply 5 years ago on Step 10

    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.


    5 years ago on Introduction

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


    5 years ago on Step 3

    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


    6 years ago on Step 2

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


    7 years ago on Step 11

    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?

    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


    Reply 7 years ago on Introduction

    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.


    8 years ago on Introduction

    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.

    3 replies

    Reply 8 years ago on Introduction

    You could actually do that! THere are actually very thin aquariums out there! Check this out: http://www.google.com/products/catalog?q=picture+frame+aquarium&um=1&hl=en&bav=on.2,or.r_gc.r_pw.&biw=1440&bih=813&ie=UTF-8&tbm=shop&cid=7490070703706333955&sa=X&ei=ViP4TeSaNYfEgAfJtKSkDA&ved=0CFQQ8wIwAA


    Reply 7 years ago on Introduction

    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...