Arduino Fish Feeder

I have a fish. Last year I had more than one fish, but I bought some of those auto-dissolving pyramid feeders to use and all of the other fish died during thanksgiving weekend. I bought more fish, and used another different type of auto-dissolving gel at christmas and again, all fish except this one died. That either means I have a murderous fish, or the dissolving feeders are horrible. Since I can’t get rid of its taste for blood, I decided to tackle the second problem.

I made an arduino based fish feeder! Really it sounds kind of fancy but it only took roughly 15 mins of work to prototype. It took more time to figure out the proper dispense amount and to write this post. Sometimes the simplest solutions are the best.

So while I could be sitting on the next best thing, an idea worth millions if not billions, I’m going to share the intimate details with how I constructed this fullproof system. (It worked with a 0% fish death rate this past thanksgiving and christmas).


See the video with sound as it was initially designed here. Note some people don’t like the musical accompaniment.


The spice bottle filled with food is left open and taped to the servo at angle zero. When the servo wants to feed the fish it twists the bottle 180 degrees. Food falls out, but also clogs the holes so a very limited amount actually is dispensed. The amount dispensed is pretty consistent. The servo immediately rights itself back to angle zero and waits for the next feeding. The food and spice bottle will both determine the quantity dispersed. I tried using a salt shaker but nothing worked. Selection of the bottle is the most important thing to test.


  • Arduino
  • Servo
  • Unused Spice Bottle
  • Tape
  • (optional) Box



I tried to calculate the amount of food I was feeding my fish. I was feeding about 3 pinches of food once a day, this equated to about 70 pellets. Later I felt like this was a bit much so I decided to round down from this amount. Believe me this fish is big.

I attached the feeder mechanism to a plastic container, turned it on and counted the dispersed pellets. Through 8 iterations, I observed an average dispersal of 32.5 pellets with a standard deviation of 7.5.

Over thanksgiving break I operated the system at one nourishment per 12 hour interval. Over winter break I operated the system at one nourishment per 16 hour interval. The fish seemed alive after both times being robo-fed.


Do you really need example code for this? Maybe I should try to sell you my code, I could be rich with my elaborate proprietary algorithms. For now, I’ll share. Perhaps in the future I’ll try to sell this code for some sort of $10 fee. No putting it on pirate bay you scumbags! FISHFEEDERMAXIMUMEFFECTIVENESS.pde


If you want to use this for your fish, find a spice bottle and try it out! Be sure to test it for a couple days first. I first tested it with a plastic container, and then plugged it in for real a few days early. I was sure to be around at the feeding times to be sure everything worked as desired. You can vary the amount dispensed by increasing/decreasing frequency, or by taping over some of the holes on the spice bottle. Up to you!

If you actually do this let me know ( If you do this and your fish dies, maybe don’t let me know because it will make me sad.

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