How to Create a Lightfish




Learn, how to create lightfishes, also called LED-Swimmies: Highly lucid fishes.

The artist Karl Klar did an installation in the public space, which was placed in the construction site of the new Ars Electronica Center in Linz, Austria. To vivify the flooded reservoir, 500 lucid fishes got placed into the see - plastic fishes with bright battery-powered LEDs in their inside.

They got put into the construction site at the evening of the 16. September 2007 to illuminate the whole place. The colorful glow coming out of the reservoir integrated the building site in the city of lights. The fishes symbolize the transition from the natural state of the meadow, which was there the last hundred of years, to the new modern technical museum.

Furthermore, it was possible to fish the lightfishes from the construction border using fishing rods with magnets. The fishermen and -women could take their booty with them as a trophy. This was possible in the night and 350 of the 500 fishes got catched by the audience.

In this instruction I will show you how we did the fishes.

For more information about the installation check out http://www.karlklar.at

Step 1: Equipment

You need this equipment:
1 plastic fish
1 battery (CR 2032)
1 2x2cm piece of metal
1 rubber band
1 hot glue pistole
1 carpet cutter
gaffer tape

Step 2: Open the Fish

First, you have to get the plastic fishes - the company, where I bought them doesn't exist any longer, so you have to find similar toys.

Cut a round hole in the fish with a carpet cutter, attention to your fingers!

Step 3: Attach the LED an the Battery

1. Attach the bent LED with the rubber band to the battery.
2. Put some gaffer tape firmly around it.

Step 4: Glue the Pieces Together

Glue the LED/Battery to the metal piece and then inside the fish.

Step 5: Close the Fish

Use the hot glue to close the fish again and let it dry a minute.

Step 6: Finish!

Now, repeat the first five steps 500 times and drope them in a see at night.

Check out for more pictures of the installation lightfishing.



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    32 Discussions


    10 years ago on Introduction

    hi.. i am a student and frm singapore.. r all the items needed available in singapore or what other materials can i used to replace items that are not able to find here! i am working on a project of lightings, as in making one like the lightfish!

    1 reply

    Reply 10 years ago on Introduction

    well, I don't know, which material is available in singapore, but I guess that the only uncertain thing will be the fishes - they got produced in germany, but I am sure, you can find similar fishes in singapore.

    do some googling =)


    11 years ago on Introduction

    I think you should add a resistor and maybe a toggle switch or a rocker switch somewhere, and put it in your pool because if you put it in the ocean it would be cool too but then you would waste money and i don't like wasting. Also, if you use a switch then when you put it in your pool you can take them out when you want. Great instructable still!!

    5 replies

    Reply 11 years ago on Introduction

    Oooh... Better yet, run some exposed wires on the outside to make a water-sensitive switch. Then, the fishes only light when immersed, and they go out when removed from the pool. The chlorine should make the water conductive enough, and the battery voltages should be low enough so as not to shock anyone.


    Reply 11 years ago on Introduction

    are you shure, that this will work? please write me a message, which material you would suggest to use. And: would it work in normal water? Because in my project they got put in normal river water.


    Reply 11 years ago on Introduction

    I'm not sure if it'd work or not, but it' be easy to test, Make a throwie, just leave an open circuit between the LED and the battery one side (adding some long leads to make a test probe), then dip said leads in the river, and see if it lights up.


    Reply 11 years ago on Introduction

    okay, I will try that, but I think, it will affect the life expectancy of the battery, or am I wrong?

    Looks like the fish are swimming on the water rather then below the surface. How about using rubber duckies instead? There are plenty of places you can get them. Of course it would be even cooler to have submerged fishies glowing and blinking under water.

    1 reply

    yeah, they are swimming on the surface. They water, in which they got put was so dirty, that you would not have seen them 10 cm under surface. In a pool, it would be possible, but how can you make them staying in the water (instead going completly to the top or the bottom?)


    Reply 11 years ago on Introduction

    pretty long, depends on the batterys. Right now, the first prototype is still working and about two months old.