Proper fish care begins with diet, which is the key to maintaining health and longevity in aquarium life. Due to the array of species available for fish keepers, this can lead to uncertainty about what your fish should be eating, how much food they need to eat, and how often they need to be fed.
As a general guideline, it is best to try to replicate the diet a fish would eat in their natural habitat. Each species has evolved to metabolize certain foods and nutrients in ways that allow for optimal growth, energy, and even appearance.
Fish owners should begin by understanding whether their fish are herbivores (eating plant matter and algae), carnivores (eating meat by either scavenging or hunting), or herbivores (needing both plants and meat in their diet).
Herbivores, such as cichlids, plecos, and catfish, need to feed more regularly, for the simple reason that vegetation is less dense in nutrients and calories than meat. They also lack a true stomach, and need to eat more regularly to maintain their metabolic activity.
Carnivores, such as bettas, oscars, and tetras, do not need to be fed as constantly. Their bodies are accustomed to eating large amounts of calories in a short time span, and going longer between opportunities to feed. The size of their stomachs allows them to stay full for longer periods of time.
Omnivores, which include goldfish, rasboras, and barbs, will eat regularly. They are accustomed to foraging for plant matter or detritus between feedings, but this should be supplementary to their diet. Omnivores still require regular feedings with foods specific to their needs.
What Should I Feed My Fish?
Your best strategy with any fish species is to replicate the diet they would eat in the wild. Fortunately, both specialty aquarium stores and general pet stores stock a wide variety of options for both fresh and saltwater tanks.
Carnivores will generally be able to consume a range of protein sources, including bloodworms, brine and other small shrimp species, and zooplankton. These generally come frozen or freeze dried. Larger carnivorous fish may be stimulated by feeder fish, live shrimp or small insects, such as crickets.
There are a number of flake varieties available for carnivorous fish, as well as crisps, which are thicker flakes, pellets, and tablets. The nutritional values in these will vary, as they are tailored to the needs of different fish species. Betta fish, for example, will do best with foods that promote their vibrant coloration, as well as supplying them with the protein they need in their diet.
Herbivores also have their own specific needs. Some herbivores can be sustained on flaked foods that give them sufficient nutrients. Others that are naturally bottom-feeders may enjoy wafers, which sink to the bottom of a tank. Wafers also dissolve slowly, allowing the fish to graze for extended times.
Owners will also add fresh vegetables, such as chopped squash, leafy greens, or peas, to the tank for herbivores to nibble at. They also may enjoy live plants that grow in their tanks. Some species will forage for algae that may grow on the aquarium surfaces, and others may even need specific algae supplements. These supplements can be found in tablet or pellet form.
For omnivorous species, flakes, crisps, wafers, and pellets can be found that blend both meat and plant matter. Owners may also find it easier to allow them to feed with other tank mates.
How Much Should I Feed My Fish?
Fish, like most animals, will often eat more than they physically require in one setting. In nature, there is no guarantee when a next meal comes along, so they have to consume as many calories as they can at each opportunity.
In a fish tank, however, this can result in overeating or overfeeding. Your fish may swim excitedly during feeding times, as though they are starving. If excess food is provided, however, they may leave portions of it uneaten. The excess food starts to spoil, and can have a detrimental effect on the quality of the tank water as it decays. The water may start to appear cloudy, nitrite levels may rise, and algae growth can accelerate.
For most aquarium species, feeding them an amount they can consume within three to five minutes is sufficient. This may require some trial and error when new species are introduced to a tank environment. Starting with less, rather than more, is advisable. If you notice excess food, use a net or siphon to remove it from the tank, rather than allowing it to spoil.
Juvenile fish have higher caloric needs due to their growing bodies. If you have younger fish in your tank, provide them with more food than you would feed their adult counterparts.
How often should I feed my fish?
Feeding schedules can vary from fish to fish, and species to species. This will generally depend on whether they are carnivorous, herbivorous, or omnivorous.
Meat is more dense in calories and nutrients than plant matter, so carnivores will need less frequent feedings. Some species will thrive on one feeding per day, while others will do better with two. The proteins, fats, and other nutrients found in meat take longer to digest than plant matter. Additionally, carnivores have larger stomachs to sustain them over the digestive period.
Herbivores have smaller stomachs and larger digestive tracts. This allows them to break down the plant matter they consume more efficiently, but it also means that they cannot eat as much in one meal. Herbivores do better with more frequent feedings. Generally, two to three feedings per day is required, depending on the species. Food that sinks to the bottom also allows them to graze throughout the day.
When should I feed my fish?
Like most animals, fish will grow accustomed to eating at specific times of day, and will generally be healthier and more active on a regular schedule. For fish that eat twice per day, spacing their meals out every 12 hours is a good rule of thumb. This allows them to have the same period of digestion between each meal time.
Feeding for nocturnal fish will differ, of course. Their periods of activity may not align with their owner’s sleep habits. Pellets, or slowly dissolving wafers or frozen foods will allow them to feed when they are hungry. Drop these into their tank before you go to bed. While you don’t get to enjoy watching them feed, this ensures that they still receive sufficient and regular nutrition.
What are signs I might be overfeeding my fish?
As mentioned, knowing the correct amount of food to feed your fish is crucial. This affects not only their diet, but the overall quality of their tank environment. An eye test can reveal if there is excess uneaten food, either by looking for detritus and waste.
You should also pay attention to the clarity of the water. If it appears cloudy or filmy, that may be due to decaying food. Algae growth is another indicator of overfeeding. Snails, shrimp, and catfish can all help to control algae levels.
Pay attention to the water parameters in your tank as well. Decaying food releases harmful compounds into the aquarium, such as nitrites and nitrates, as well as ammonia. To avoid tank pollution, limit the amount of food you provide your fish.
Diet and Care
All fish require a balance of proteins, fats, calcium vitamins, and fiber to maintain their health and longevity. The balance and source of these macronutrients will depend on whether they are carnivores, omnivores, or herbivores. Thankfully, as fishkeeping has grown in popularity, so has the variety of foods available that have been tailored to the needs of specific fish species.
Owners should be knowledgeable about the fish they purchase and add to their tank to avoid feeding problems, and to provide the correct quantity and regularity of feeding. Given that you manage these details, your fish should grow and maintain their health throughout their lifespan.