Feeding time is one of the most fun things about having an aquarium. Everyone likes to watch their fish come to the surface and eat. But did you know improper feeding is the leading cause of poor fish health? It makes your aquarium dirty, too. Proper feeding keeps your fish healthy and your aquarium water crystal clear! Here’s what you need to know about feeding your fish.

What do fish eat?

There are many kinds of aquarium fish. Some fish, like pleco catfish and African cichlids, eat an algae- rich diet, while others, such as oscars and many South American cichlids are meat-eating carnivores. However, most aquarium fish are omnivores—they eat things like algae and tiny worms in nature. But there’s more! Some fish, like small catfish, like to explore the bottom of the tank, looking for food. Fortunately, there are many kinds of fish foods, making it easy to give your fish what they like.

Common types of fish food

Flake foods are one of the most popular types of fish food. The flakes float on the surface for several minutes before sinking. Most aquarium fish will swim to the surface to nibble on the flakes—even bottom-feeders will swim to the top to grab a bite. Flake foods come in several formulas; the most common is called a “staple diet.” It contains plant and animal ingredients like algae, wheat germ, fish protein, and vitamins and minerals. Special goldfish flakes are formulated to bring out the fish’s orange and red colors. Veggie foods contain a higher percentage of plant-based ingredients.

Pelleted foods are made of similar ingredients but are compressed into a hard pellet. The pellets range in size from tiny particles for smaller tropical fish like neons and bettas to large pellets for big fish like cichlids. Sinking pellets immediately fall to the bottom of the tank, making them ideal for catfish and other bottom dwellers like loaches. Floating pellets will remain on the water’s surface while fish swallow them whole or bite off a piece at a time. It’s best to select a pellet that your fish can swallow. If the pellet is too large, it can get stuck inside the fish’s throat.

Specialty fish foods

Specialty fish foods like algae wafers, floating crisps, and crumbles give your fish variety in flavor and texture. Many fish really enjoy freeze-dried shrimp, worms, or insect larvae. You’ll also find an array of frozen foods like shrimp, worms, plankton, and algae.

Foods to avoid

Never feed your fish table scraps, bread, pasta, cereal, or other types of human or pet food. Your fish have specific dietary needs. Fish foods are formulated to be digestible and provide the right balance of protein, fat, vitamins, and minerals. Feeding them the wrong kinds of food will hurt your fish and cause water quality problems in the aquarium.

Feeding them the wrong kinds of food will hurt your fish and cause water quality problems in the aquarium.

Aquarium fish always act hungry!

Your fish will recognize you as you approach the tank. They’re curious, and many fish will learn to “beg” at the water’s surface. Don’t make the mistake of thinking your fish are always hungry! Your fish won’t starve or feel bad if you don’t feed them every time you approach the tank. The truth is, if you feed them too much, they’ll develop unhealthy fat deposits around their internal organs. This will shorten their lifespan and increase the chances of disease or other health problems.
 

How often should I feed my fish?

Nearly every aquarist asks this question. Proper feeding is a blend of art and science. The old rule of feeding is to feed twice a day and only feed what will be consumed in about three minutes. Fish don’t eat leftover food. It just gets wet, decays, and fouls the water. Skilled aquarists know how to provide a variety of foods, sometimes several times a day. You can give small amounts several times a day as long as your fish are not over-eating. Your fish should never have large, bloated stomachs after eating. Fish don’t know when to stop eating, so they’ll often over-eat if you keep adding food. 

Fish don’t eat leftover food. It just gets wet, decays,and fouls the water.

How to feed fish while on vacation?

If you are away from home for a day or two, your fish will be OK without feeding. But if you’ll be away long, you’ll want to have someone feed your fish for you. It’s very helpful to measure out each day's feeding so your friend or family member doesn’t have to guess how much to add to the tank. You can also use a battery-powered automatic fish feeder. The device automatically feeds your fish once or twice a day.

Final thoughts on feeding

Feeding your fish is fun and entertaining. You can make feeding even more interesting by experimenting with different types of fish foods. Try frozen brine shrimp in addition to flake foods. Your catfish will love sinking pellets. The most important thing to remember is not to overfeed. Your fish will stay healthy, and your aquarium will remain clean and clear.

Fish Food FAQs

How long does dry fish food last?

The nutritional value of man-made fish foods slowly declines over time. Vitamins and protein are sensitive to oxygen. Exposure to air and moisture will cause the food to become rancid quickly. Keep the food container closed after feeding, and never reach into the container with wet fingers. For the best nutrition, a container of food should be used up in six months or less. 

Can I feed my fish with more than one kind of food?

Many aquarists feed their fish with basic flake food. A high-quality flake food will provide the fish with a balanced diet. Some fish seem to enjoy munching on specialty foods like sinking algae wafers, live brine shrimp, and other foods. Variety also ensures the fish are getting all the nutrients they need to live a long, happy life.

What happens to uneaten fish food?

Once the food gets soaked with water, it begins to decay. Most fish won’t eat food that’s turned mushy. Bacteria that live in the aquarium consume decaying, uneaten food and reproduce so much that the water becomes cloudy. The decaying food can also cause ammonia and nitrite levels to rise to toxic levels. This will stress the fish and make it easier for them to get sick. 

Someone accidentally poured too much food in my aquarium!

Don’t panic! Using a net, remove as much food as you can. You can also suck out food particles with a hose or gravel siphon. If food got captured inside the filter, change the filter media. The food will rot inside the filter if you don’t clean it out. Be sure to test the water quality over the next couple of days and make water changes if the ammonia or nitrite rises.

My tropical fish won’t eat!

There are several reasons why fish won’t eat. If you’ve just added the fish to your tank, it could take several days for the fish to settle in and start to eat. Poor water quality stresses the fish and makes them uncomfortable. Test your water and make sure the pH, ammonia, and nitrite are at the correct levels. If your fish is sick, it usually won’t eat, though many fish will recover from illness and start eating again.