The Hydor Ekomixo Digital Aquarium Feeder (Buy Online) is a highly configurable feeder with an attractive design. The rotating drum along with the very good internal air circulation makes this feeder much less prone to jamming up than other feeders on the market. When the feeding drum rotates it also helps agitate the fish food in order to prevent it from sticking together and forming clumps. This feeder dispenses food by rotating the feeding drum, which allows the food to fall out of a hole on the drum. And it is made of transparent plastic which makes it easy to see how much food is left in the drum with just a quick glance. The exact capacity of the feeding drum is 3.3 fl oz (100 ml). The feeding drum that holds the flake food on this automatic fish feeder will hold up to six weeks of food. And there is a manual override button that will allow you to feed your fish any time you want. You also have the option of programming this feeder to release a single serving or a double serving with a 1-minute delay. Programming this feeder is a simple task thanks to the large easy to read LCD screen. You can program this feeder to dispense flake food once a day or all the way up to four times a day if you like. This is one of our favorite feeders because it is so simple to use. The EHEIM Automatic Feeding Unit (Buy Online) has all of the features you would want in an automatic fish feeder.