Introduction: Cheap Automatic Aquarium Feeder on the Go.

Picture of Cheap Automatic Aquarium Feeder on the Go.

Now you don't need to worry about buying an expensive automatic feeder for your aquarium.
Here is a cheap alternative you can make in a few minutes without electronics knowledge.

Step 1: Materials Needed

Picture of Materials Needed

1 Working battery clock or clock parts.
1 Small plastic can (must be light weight)
2 Thin neodymium magnets
1 Plastic pen or plastic tube

Step 2: Tools Needed

Picture of Tools Needed

1 Screwdriver (for dismount the clock case)
1 cutter knife
Some instant glue like cyanoacrylate

Step 3: Preparing the Clock

Picture of Preparing the Clock

If you have the clock parts or the gearbox, goto the next step.

Proceed to dismount the clock case for removing the front (transparent) cover.
Once you remove the transparent cover, mount again.

Carefully remove the clock hands pulling them slightly towards you, one by one.

Step 4: The Timer

Picture of The Timer

- Cut a piece about 20mm of tube from the pen. Another kind of plastic tube is ok.
- Sandpaper the the tube to make a perfect cylinder.

- Put the cylinder on the exact center of one magnet and drop a glue drop inside to paste both parts.

- Roll a piece of fine sandpaper and put it into the cylinder.
- Sandpaper turning inside the tube and check until the piece fits perfectly on the outer gear piece (where the hours hand was)

Step 5: The Automatic Food Dispenser

Picture of The Automatic Food Dispenser

- Paste one magnet on the exact center of the plastic can.

- Make a square of about 10mm on the can and cut it. (Better if you heat the blade of the knife to avoid cracking the plastic)

- Draw a 30x30mm square on a cardboard and cut it making a cross.
- Bend the tabs as shown in the picture and paste with adhesive tape to make an opened box
- Paste the box with adhesive tape by the outer lid inside the plastic can.
- Remember that the hole of the box should go clockwise to let the food go by.

Do not glue the box tho the plastic can, maybe you'll need to make a different size one in the future. Use adhesive tape to do this.

The bigger the window and the box are, more food will fall.

Step 6: Finishing the Project

Picture of Finishing the Project

Almost done!!!

- Open the plastic can and fill it with your fish favourite food (then close it).

- Take the clock and the plastic can and let the magnets do their work...

Now the clock will drop a bit of food each 12 hours (when the window is at 6 o'clock).

Enjoy it!!!!


ZaenalA13 (author)2017-05-01

Great!!! it's works....i can go with no worry

thomasplam (author)2017-03-06

hello elufo thank you very much for such a nice idea, i also made one.

First day it worked well and the second day I have encountered one problem, moister started getting inside the container and the food started sticking on the walls of the container. Did you face this issue? I just wrapped the container with aluminium foil and waiting for the result.

keeshond77 (author)2016-10-12

AWESOME! I'm doing this with a slight modification: insted of paper I'll be using aluminum from a soda can, I expect to regulate quantity of food by folding open and close said aluminium. Thanks for this genius idea.

elufo (author)keeshond772016-10-18

Thank you!

Remus-DorianA (author)2015-11-23

If you make two openings in the can you will get a 6 hour feeding interval. By using a can which has a lid bigger than the base you will have food always coming towards the opening.

Builders Shed (author)2015-11-12


kaushiknfs (author)2015-10-27

Its quite intuitive and ingenious solution, i've built one on the same lines but i dont get the need for couple of things

1. The magnet, i could directly fix the box the hour clock hand

2. The pen chop, i found it easier to fix the plastic box directly to the hour dial than through the pen cut.

Also i guess havinh a pen cut and magnets will add more weight and the dial.

Its posible i could be missing the primary reason for those, if so let me know.

tee1964 (author)2009-05-29

I have an auto feeder that I bought at a pet store. This idea is great as it allows the fish to get fed at the same time each day and they never miss a meal and allows you to leave on holiday for a week or two. My feeder allows me to leave for a month without worrying. Anyone have any ideas how I can keep my water level in the tank constant? If so let me know and I'll be all set for another vacation! BTW, The feeder is placed on top of the tanks allowing the plastic can to rotate freely. Thanks for sharing your idea!

sohailkhan246 (author)tee19642015-09-10

use football valve like the one which is present in Air Coolers

bwpatton1 (author)tee19642009-06-08

How many gallons is your aquarium? If large enought you could implement some sort of device, that works the same way as a toilet, when water drops below certain point then tank fills appropriatley. Viola,

manoj j sm (author)2015-01-12

Great !!!!!! thanx alot.........

BIGDOG1971 (author)2013-02-02

Very Nice, a simple and effective idea.

TaNviR77 (author)2011-11-10

Thank you so much, gonna build mine soon :) I have some modifications in my mind. Don't worry I will put my pics.

gapak (author)2011-04-17

Some advice: don't use automatic feeders for your aquarium. There are only disadvantages:
1. The food might cake together from the heat of the lamps, it is possible to disturb the working of the device.
2. The food needs to be stored at room temperature, the heat of the lamps will cause the vitamines to break down.
3. Every week fishes need to get a day of fast. Also 2 days a week it's important you give your fish frozen food to keep them in optimal health.

Feed your fish by hand each day 1 time and use the weekend or vacation food if your out.

rivan (author)gapak2011-04-17

But, if it away from lamps and used only when it's impossible to feed them by hand? Sorry about the english, my default language is PT-BR ;)

gapak (author)rivan2011-04-24

If it's impossible to feed them by hand you have to use weekend or vacation food. During non-vacationperiods you have to feed them by hand to make sure there's variation in their diet.

rivan (author)2011-04-17

Impressive. I'll make one today.

vwalpola (author)2011-01-18

Nice work! i was looking for a autofeeder. Now i can make this gadget. Thanks for the idea.

iewaxu (author)2010-12-24

great job .....

aerika (author)2010-12-02

That is pure brilliant! So simple and elegant.

fishmaniac (author)2010-11-24

geddemnit!! you are so genius..thanks a lot for the instruction

verdastel (author)2010-08-17

I have been thinking of similar device but the plans which have crossed my mind were all too difficult to construct, but this instructable is cool. It's affordable and simple! I'm gonna make it myself, thanks a lot for sharing elufo!

flashj (author)2010-04-20

This looks great, I'll be watching for a cheap clock to try this!
Question: Is there a problem with the fish food missing the box and openning or does the constant rotation ensure food always gets thru the hole and into the tank?

elufo (author)flashj2010-07-24

Second one ;)

the mechanical engineer (author)2010-04-20

wow. cheap, simple and easy. very nice. 5*

tags-g (author)2010-02-17

nice device the way, do i need to set the clock always after every feed it makes?..or it will just go on in one set only?...

elufo (author)tags-g2010-02-18

You only need to set the clock the first time.
The device feeds one time each 12 hours until battery runs out of energy.

sergey.p (author)2010-01-15

Very nice device, indeed. I should try this as well.
My fish needs different food: chips, flakes and small sand food.
Do you have any idea to make the same kind of feeder for different food types?

anoyzz (author)2010-01-05

wow....nice job bro...

cannonwashburn (author)2009-09-28

First of all great Instructable. This is very similar to one I bought at my local fish store. The only issue is that if you have a tropical tank there will be some humidity. This means the food could get damp in the feeder and spoil. Again great idea.

jimmiek (author)2009-08-23

How long is 20mm in American inches?

elufo (author)jimmiek2009-08-23


HAZMAT2364 (author)2009-08-10

Any way to make the period of time that it feeds any longer??

LemonLily (author)2009-04-07

Where do you put this?

elufo (author)LemonLily2009-04-08

There are many ways to put it. I used a piece of plastic across the aquarium edge.

roswellgeorge (author)elufo2009-07-30

How do you remove the chlorine ?

loricollins (author)LemonLily2009-04-08

Just looking at the pictures on this page, I'd say that it was meant to overhang the edge of the fish tank. But, that's just a guess.

steed1172 (author)2009-06-26

nice i will HAVE to make this...much cheaper then the ones in stores... i see um for 20-50 bucks!! thanks i will now be able to sleep in more at times :P

bassmonkey (author)2009-04-21

dont you have to put in more food every day?

elufo (author)bassmonkey2009-06-16

It depends of the size of the plastic can. Mine at medium filling is about 1 month.

bassmonkey (author)elufo2009-06-17

impresive! check this out f u like fish

J@50n (author)2009-06-16

haha i made this and at 10:30 tonight i can rate it! Ill be back dont worry!

elufo (author)J@50n2009-06-16

Nice! Could you post pictures of yours?

J@50n (author)elufo2009-06-16

haha i cant now.. my clock was too big and it all broke...i needed the smaller clock but i went to walmart and got a real one for only 12 buck but good instructable! im gunna do a 5* because its a great idea and it was fun!

omnibot (author)2009-04-09


elufo (author)2009-04-08

Thanks to all for your comments :D

Lithium Rain (author)2009-04-07

I've been thinking about this problem in my head for some time - never could quite work out a good mechanical solution. What a nifty device!

crait (author)2009-04-07

Very cool!

jessyratfink (author)2009-04-07

This is a genius idea! Thanks for sharing. :D

gotclawz1 (author)2009-04-07

Thank you so much, this is exactly what i needed i can't wait to make one

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