I will start with dried food. This is the most common form of food that aquarists feed to their aquarium inhabitants. This category consists of the flake and pellet foods you can usually find on the shelf at the local fish shop. There is no surprise on what is in the food since all containers have a list of ingredients on the side. Generally, you can't go wrong with dried foods. Most brands contain all of the necessary minerals that your inhabitants need. Two words of caution with these types of food. First, they lose some of their vitamin content over time due to air exposure. This means that, although you would love to buy those huge volumes of flake food to save money, try to stick with portions that come in the moderate-sized containers. If you still insist on buying those large quantities, try and keep the bag out of direct sunlight - sunlight increases the depletion rate of the food. Second, pay attention to the flake food as you put it into your aquarium. Often it tends to float for a few seconds, allowing it to get sucked up into the filtering system (this depends on your filtering design). If this is the case, try presoaking the food by taking a pinch of it in your hand and holding it underwater for a few seconds. Then release it. The food should slowly sink, reducing its chances of getting pulled into your filtering system. Food that gets into the filter will quickly clog your prefilter, and it goes without saying that this is not a good thing. If you are unsure about the type of food to feed your fish, this is the safe bet. About the only thing that you can do wrong here is overfeed - something which can happen no matter what you are feeding your fish. Just remember that fish will always appear hungry (unless they are sick), so you need not use that as a gauge for feeding. Simply feed only once a day in moderation.