Fish need to be fed often, but what they eat and how much they eat are important for their health and well-being.
As a fish owner, ensuring your aquarium residents get optimal nutrition is key to keeping them healthy and thriving. But with over 30,000 fish species swimming the seas and freshwaters, diet can vary greatly between different types of fish. So what exactly can fish eat?
The diverse dietary needs of fish depend on a variety of factors. These include:
- Fish species
- Age of the fish
- Natural diet in the wild
- Water conditions
- Health requirements
Understanding what food items your particular fish can and should be eating is crucial for providing a balanced diet. Read on for a complete guide to fish diet and nutrition.
Types of Fish Diets
Fish eat a wide variety of food in the wild But their dietary preferences generally fall into a few main categories
Carnivorous Fish
Carnivorous fish are meat eaters. They hunt kill and consume other fish, invertebrates, insect larvae worms, zooplankton and other meaty foods. Examples include
- Cichlids
- Bettas
- Oscar fish
- Arowanas
- Goldfish
Carnivorous fish require high protein foods like bloodworms, brine shrimp, and meaty pellets
Herbivorous Fish
Herbivorous fish feed mainly on plant material and algae. Common herbivorous fish include:
- Plecos
- Silver dollars
- Cory catfish
- Mystery snails
- Shrimp
These fish graze on foods like algae wafers and blanched vegetables.
Omnivorous Fish
Omnivorous fish eat both plant and animal material. Many common aquarium fish are omnivores, such as:
- Tetras
- Barbs
- Mollies
- Guppies
- Angelfish
An omnivorous diet includes flakes, pellets, bloodworms, brine shrimp, and veggies.
Detritivores / Detrivores
Detritivores feed on decaying organic debris and biofilm on surfaces. Examples include:
- Loaches
- Plecs
- Catfish
These fish eat sinking wafers and tablets that settle on the tank bottom.
Nutritional Components Fish Need
While fish aren’t picky eaters and will eat a wide range of foods, their diet should contain optimal amounts of:
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Protein – For proper growth and development. Most fish need 40-50% protein.
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Fats and Carbs – Provide energy. Fish need around 5-10% fat content.
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Fiber – Aid digestion and regulate metabolism. Obtained from veggies.
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Vitamins & Minerals – For enzymatic processes, metabolism, bone health.
Getting the right nutritional balance depends on the foods you offer. Let’s look at some options.
What Fish Can Eat: Dietary Staples
Most freshwater fish sold today are bred commercially and accept flake or pellet foods readily. Here are some staple diet items to feed your fish:
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Flakes – Flaked fish food provides balanced nutrition in a convenient form. Top choice for most community aquarium fish.
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Pellets – Sinking or floating pellets catered for popular species like tetras and barbs. Offer variety.
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Algae wafers – Grazing fish like plecos will nibble on these along tank surfaces and floor.
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Freeze-dried foods – Bloodworms, brine shrimp, daphnia and tubifex worms are protein boosters.
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Fresh veggies – Blanched greens like zucchini, peas, spinach for omnivores and herbivores.
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Supplements – Soak dried foods in vitamin drops or stimulants for picky eaters.
Varying these basic foods will cover all dietary requirements.
What Fish Can Eat: Supplemental Treats
In addition to daily flake or pellet feedings, you can provide supplemental treats. Some tasty options include:
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Live blackworms – Excellent for picky or recovering fish who need stimulation to eat.
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Frozen bloodworms – Predatory fish like bettas will relish these protein-packed, meaty worms.
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Brine shrimp – Both live and freeze-dried brine shrimp make an enticing, nutritious snack.
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Daphnia – Small aquatic invertebrates called daphnia wiggle like live food to spark interest.
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Crickets or mealworms – Some larger carnivores like oscars may eat small insects.
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Shrimp pellets – Made of concentrated ocean critters like shrimp, krill, plankton.
Treats provide enrichment and encourage foraging behaviors. Sparingly feed treats no more than once or twice a week.
Foods to Avoid Feeding Fish
Some common human foods should be avoided when feeding fish, including:
- Chocolate, coffee, soda
- Citrus fruits
- Hard crunchy items like chips that can injure jaws
- Raw potato or beans contain enzymes harmful to fish
- Anything with added salt, spices or oils
Stick to aquarium-grade fish foods specifically formulated for nutritional balance.
How Often and How Much to Feed Fish
Use these guidelines for determining feeding frequency and amounts:
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Feed most adult community fish 1-2 times per day.
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Only feed amounts they can completely finish within 2-3 minutes. Don’t overfeed.
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For young, growing fish feed 3-4 smaller meals per day.
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Adjust food amounts based on fish species size and unique needs.
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Fast 1 day a week for better digestion.
Pay attention to if fish lose interest in food or appear lethargic, which are signs of over- or underfeeding. Adjust your regimen accordingly.
Dietary Needs of Specific Fish
While the standard prepared fish foods will suffice for most community aquarium residents, some species have more specialized needs.
Goldfish – Require significant plant matter in their diet along with protein-rich pellets and treats.
Betta fish – Insectivores that prefer live or frozen foods like bloodworms and brine shrimp.
Cichlids – Tend to be predatory and need meatier foods like shrimp pellets and crickets.
Plecos – Algae eaters that thrive best on sinking algae wafers and blanched veggies.
Research the nutritional preferences of your fish species for a more custom diet.
Fry and Baby Fish Feeding
Young fish and fry have higher protein requirements for growth and development. Newly hatched fry eat:
- Powdered fry starter foods 3-5 times daily.
- Newly hatched brine shrimp for protein-rich nourishment.
- Finely crushed flakes once they mature after 2-4 weeks.
Gradually reduce feeding frequency as fry grow.
FAQs About Fish Diet
New fish keepers often have some common questions when starting out. Here are answers to some frequently asked questions about fish diet and nutrition:
How often should you feed fish?
Most adult fish do well with 1-2 small feedings per day. Feed when lights come on in morning and before lights out at night.
Do fish get thirsty and drink water?
Fish absorb water through their gills and skin – they don’t drink water like humans and pets do.
What human foods can fish eat?
In small amounts, cooked peas, shelled shrimp, spinach and zucchini can supplement some fish diets. Avoid citrus, dairy and salty foods.
Can you overfeed fish?
Yes, overfeeding leads to water quality issues. Only feed an amount fish can eat within 2-3 minutes, 1-2 times daily.
Do fish tanks need heaters?
Tropical fish require water temperatures between 75-82°F – heaters help maintain temperatures. Hardier fish like goldfish don’t need heaters.
Providing Optimal Fish Nutrition
From hardy goldfish to choosy bettas, giving your fish a nutritious and balanced diet tailored to their needs is crucial for their health. Use these fish diet tips to feed flakes, pellets, treats and veggies in the right amounts. Your aquarium inhabitants will be happy, active and ready to show off!
What To Feed Your Fish | RSPCA – RSPCA
Fish need to be fed often, but what they eat and how much they eat are important for their health and well-being.
A well-balanced diet for pet fish
You need to buy the right type of food for your fish. For example, dont buy your goldfish tropical fish flakes. This is because they contain different levels of nutrients.
Its also important to supplement fish food flakes with other foods for balanced nutrition and enrichment.
For example:
- Goldfish love chopped vegetables such as peas and spinach.
- Tropical fish vary in what theyll eat. If the fish is frozen, make sure it is fully thawed first. Then, crumbled boiled egg yolk and lettuce leaf may work.
- Some types of plecos need to eat plants, like potatoes, or pieces of wood to chew on.
- Water fleas, also known as daphnia or brine shrimp, are great for tropical fish and are easy to find in frozen packs. Because they are high in protein, you should only give goldfish small amounts of them.
Different tropical fish species may need their food given to them in different ways. Middle and bottom-dwelling species will need their food in quickly sinking food or compressed food tablets. Nocturnal species, like some catfish, need to be fed last thing at night.