EHEIM Automatic Fish Feeder Review (Model 3581)

Easy to use automatic fish feeder keeps your fish fed while you're on vacation.

When I first got a fish tank, one of the things I didn’t really think about was: What happens when I go on vacation?

The first time I went on vacation, I wasn’t really sure what to do. I was about to leave my house for the airport and then I saw the fish tank. So I overfeed my fish and hoped for the best. I thought they’d be OK for a couple days without food. I was wrong. Unfortunately, my algae eater was cannibalized by the other fish while I was away. He was my favorite fish and I felt terrible.

But years later, I’m now a fish tank veteran and know better. And when I go on vacation, feeding my fish is no longer a problem thanks to the Eheim Automatic Fish Feeder.


  • A fish tank
  • Fish (Tetra or Betta)
  • Fish food
  • AA batteries (included)

NERD NOTE: Tetra is a species of small freshwater fish from Africa, Central America, and South America. They belong to the biological family Characidae and to its former subfamilies Alestiidae (the “African tetras”) and Lebiasinidae.

Automatic Fish Feeders vs Food Bricks

If you own a fish tank and are going away for the weekend, or on vacation, you basically have 3 options if you really care about your fish:

  1. have a neighbor come feed them
  2. buy vacation fish food bricks
  3. buy an auto feeder

EHEIM Automatic Fish Feeder Review (Model 3581) 1Personally, I’d rather not give someone access to my house. And would you really entrust your aquarium to somebody who doesn’t know anything about aquatics?

If you are looking for a low-cost solution to feed your fish while you are away, then you might want to research “vacation food bricks” for your fish. For example, you can feed 1-3 betta fish for up to 7 days with Pro Balance Betta Blocks. Each food block releases tubifex worms, bloodworms, daphnia, and white shrimp… a regular smorgasbord for your betta fish. Different types of fish require different types of food so do your research first.

The food bricks are an easy low-cost solution, but what happens if you need to go away for more than 7 days? Or what if your fish eat special food that doesn’t come in bricks?

Sounds like you need an auto feeder.

Eheim Automatic Fish Feeder

Eheim is a well-known name when it comes to professional fish care. They make everything from pumps and filters to accessories like auto feeders.

The Eheim 3581 “Feed-Air” Digital Automatic Feeder is by far my favorite auto-feeder because it’s so straightforward and easy to use. The Eheim 3581 lets you program up to 4 daily feeding cycles of flake food or granules, choose between a single portion, a double portion with 1-minute interval, or manual override.

The programming interface is simple. All your programmed choices are presented on an easy-read LCD screen. The EHEIM auto feeder feeds your fish on a regular daily schedule that you define. You decide when the fish should be fed. Double dosage of the food is also provided in the programming if you want to feed once in the morning and once at night. “Snacks between meals” is also possible at the press of a button at any time. The batteries last at least 3-5 months but a warning system informs you of low battery power.

I also really like the transparent reservoir. It lets you see your fish food allowing you to monitor food level “at-a-glance.” Here’s a size comparison photo of the Eheim next to an iPod Touch.

Eheim Fish Feeder


You can use household items like canned food to help position the Eheim automatic fish feeder. I like cans because they are heavy and won’t easily get knocked over. Some of the “stacking” configurations I’ve done lately are ridiculous. The trick is finding the right balance and the right height of the tin cans.

Eheim automatic fish feeder

Food Dampness

One of the things you really need to consider when buying an auto feeder is “dampness” of the food. Cheaper auto feeders lack an integrated ventilator. Because auto feeders are usually very close to the tank, they tend to allow moisture into the food reserve. As a result, moist fish food will spoil and clog the unit.

The Eheim doesn’t have this problem. It has a built-in ventilator that prevents moisture issues. This aerated feeding chamber takes in dry air before feeding and helps keep all the food in the 100 ml chamber dry down to the last flake. So maintenance is almost non-existent.

How to Replace the Batteries

  1. Unscrew the battery compartment (Only if necessary. Not all models have screw secured battery compartments).
  2. Push the tab located on the bottom forward portion bottom of the fish feeder in, and pull up on the battery compartment lid.
  3. Place one AA battery, positive (+) end up, in the back of the battery compartment. Slide a second AA battery, negative (-) end up, in the front of the battery compartment. Click the battery compartment lid over the batteries.
  4. Push the food canister away from the control head of the fish feeder. Place a thumb on the recessed area of the food canister. Push toward the top of the canister to remove the canister lid. Set the canister lid aside.
  5. Fill the canister to the “Full” line. Push the canister lid onto the canister. Push the assembled canister onto the control head. The canister will snap when seated. Slide the adjuster located in the recess area of the canister to the amount of food required for your fish.
  6. Set the fish feeder on top of the aquarium with the back of the canister over the aquarium water.
  7. Press the “Set” button. Press the plus (+) button to adjust the hours of the current time. Then press the “Mode” button and press the plus (+) button to set the minutes of the current time. Finally, press “Set” to store the current time.
  8. Press the “Mode” button to set the first feeding time. Set the hours and minutes of the feeding time as described for the current time. Press the “Mode” button a second time to enter the number of times to feed your fish per day. Press the “Set” button to save the feeding time(s).
  9. There are 4 possible feeding times possible. They are represented by the small numbers along the top of the LED screen. When you are done, you should see a down arrow next to the feeding number.
  10. Press the “EHEIM” button to use the feeder feed your fish manually between set feeding times.

Eheim automatic fish feeder

fish feederFinal Thoughts

I’ve owned an Eheim auto feeder for several years and have even purchased them as gifts for other friends with fish tanks. I recommend this product without reservation.

Whatever you decide to do, make sure your fish get fed while you are on vacation. Replace the battery every 6 months or so and this auto feeder will keep you and your fish happy for a long, long time.

With the fish taken care of, all you’ll have to worry about is your houseplants.