Expert Guide : Food for freshwater fish

When it comes to feeding the animals that inhabit our tropical freshwater aquariums, we face a multitude of formats, colors, compositions, brands, and labels to choose from. The variety of foods available to hobbyists grows daily, leaving even experienced aquarists in a dilemma about which food to choose. This article will talk about food for freshwater fish in home aquariums.


Types of Freshwater Fish Food

When we started researching the best foods for the fish in our freshwater aquarium we found a wide range of options. Feedings can range from commercial dry foods to live, fresh, and frozen foods. Each food has its specific purpose and target species.


Pelleted and Flake Foods

Commercial feeds in pellets and flakes are the most common and available options being very convenient; open the jar and feed it to the fish.

These foods are developed through research and technology, and some highly efficient labels can reach high values. In theory, nutritionally speaking, these feeds can be used uniquely in the diet as they provide all the nutrients that fish need.

You can find pellet foods in many shapes, sizes, and densities. Some pellets are made for bottom-dwelling fish (like pellets for plecos) and sink quickly. Others are for fish that feed on the surface (like betta), the pellet will float or sink slowly.

This difference exists because each fish has a unique eating habit, which must be taken into account when managing food in our aquariums.

Flakes are as popular as pellets and are available in different sizes and densities.

Commercial dry foods should be the basis of the diet of most freshwater fish in domestic aquariums, and the greater the variety offered, the better for the animals.


Frozen and Freeze-Dried Foods

Frozen and freeze-dried foods are also great in terms of nutrition, convenience, and practicality. Some of these frozen foods are close to what fish would find in nature, and using them has many advantages.

Rapid freezing and freeze-drying are techniques that maintain much of the nutritional integrity of the ingredients, preserving the essential nutrients for use by the fish.

You can find them in specialized stores, with different foods available. Brine shrimp, daphnia, bloodworms, tubifex, and mosquito larvae are found frozen as biomass or freeze-dried.

You can offer frozen foods directly in the aquarium. This food is often divided into the correct portions, reducing handling and potential contamination. Freeze-dried foods must be hydrated before being offered to fish; otherwise, they can expand within the digestive system, causing problems.

The versatility of these types of food is high, and you can use it in different ways. They can be used as a regular part of the diet or as snacks between meals.


Live Foods

Live foods, from the point of view of animal behavior and well-being, are the perfect food. When offering live food it’s a feeding frenzy, with the fish actively chasing and capturing the food. Daphnias, brine shrimp, insects, and larvae are some foods easily found in pet stores.

In addition to being a sensational source of nutrients for fish, live foods are what carnivorous and omnivorous fish feed on in the wild. Live foods make your fish hunt, and using their brain is a great practice to break the monotony and keep your fish happy and healthy.

Although they have numerous advantages, we must take some when using live foods safely. As live food is mostly invertebrates that inhabit aquatic places, some can carry pathogens. You must ensure that live foods come from hygienic, reliable, and contaminant-free sources.

Use live foods as main foods, alternating with commercial feed or as snacks. It is vital to avoid oversupply of these foods, as fish can become obese and malnourished, and quickly degrade water quality.


Vegetable Foods

You should use foods of plant origin exclusively in the diet of omnivorous and herbivorous fish. Just like foods of animal origin, those of plant origin are available among many commercial and fresh foods.

In addition to food pellets and flakes formulated for herbivorous fish, we find other foods available. The use of spirulina, an algae, is growing more and more. In addition to being a rich source of protein, this algae contains many pigments, which will improve the color of the fish.

Fresh, blanched, or steamed vegetables are part of a healthy diet for herbivorous fish. Broccoli, zucchini, pumpkin, spinach, carrots, and peas are examples of vegetables with high acceptability. Cooking or blanching is not always necessary, but it makes the food more tender and some nutrients more accessible to the fish, which helps prevent digestive problems such as bloating.

Use fresh foods alongside specialized commercial foods.


DIY Foods

Preparing your food is far from ideal, but it is an option attracting more and more fearless aquarists. The problem is that the hobbyist will hardly have the knowledge or experience to formulate a feed that serves the fish precisely without degrading the water quality and providing all the nutrients that fish need.

Even with all the difficulty, some aquarists believe that making food for their fish is the best for their fish diet, as it allows the choice and proportion of ingredients. However, it is vital to highlight that, without laboratory analysis and long-term research, this approach is completely holistic and should be discouraged, especially among amateurs.

When formulating food, professionals dedicate years of research and expensive and unique equipment to measure nutrient content, absorption of food by fish, non-loss of nutrients in contact with water, and many other things that a hobbyist does not have access to or knowledge about.

Despite the many recipes available to make fish food, it’s essential to have a solid understanding of the nutritional needs of the fish species and the chosen ingredients.

Even with so much difficulty, homemade foods can be made and used as adjuncts to a commercial diet in small quantities and right before the aquarium undergoes maintenance with a water change. This reduces nutritional deficiencies and also the rapid degradation of water.


Nutritional Needs of Freshwater Fish

Talking about ornamental fish nutrition for aquarists is not easy, especially with the misinformation we find out there. For those who are not animal health and nutrition professionals, it is sufficient to understand the nutritional needs of fish and how to select good foods. This is the best way to provide a diet that promotes health, vitality, and vibrant color without compromising the health and longevity of the fish.

Within an ideal diet, each nutritional component is in an ideal amount. The nutritional composition is the responsibility of the ingredients used to compose the food, as each one has its own nutritional and digestible values. Furthermore, each ingredient will have a specific level of nutrients used by the fish, ingredients rich in protein (for example) will have no nutritional value for certain animals.

Now let’s talk about how to read a food label to find the perfect food.



When we talk about animal feed, the first thing that comes to our mind is the protein content. From the point of view of an animal nutrition professional, the protein content is of little importance in the animal’s entire diet; it is more important to look at the source of protein.

Carnivorous fish will benefit from excellent protein intake from foods made with ingredients of animal origin, and the opposite will be true for herbivorous fish. This means that when we feed a carnivorous fish food where the protein comes from corn (even if in low quantity) the use during digestion will be low.

Proteins are the main constituents of the animal body, playing a crucial role in the development and reproduction of fish.


Fats (Fatty acids)

Fat is essential in fish nutrition, providing energy and helping maintain the structural and functional integrity of the organism. For fish, the food must be rich in PUFA-type fat, but in low quantities in the diet.



Carbohydrates are an energy source for maintaining a good balance in the body. Omnivorous and herbivorous fish need external sources of carbohydrates in a large amount included in the diet (up to 40%). On the other hand, carnivore fish need a low amount, which they obtain through protein intake.


Vitamins and Minerals

Vitamins are a problem in fish feed and may be responsible for the high price tags on some labels. Vitamins play a vital role in various biological functions, from growth, reproduction, immune response, and proper functioning of organs.

Minerals are essential for forming and maintaining the fish skeleton and body; a large part of these minerals come from food and water.

Some vitamins (such as vitamin C) are highly diluted in water. This means the food will lose the vitamin to the water and not begin ingested by the fish. Because of this problem, manufacturers use high-quality vitamins, which are very expensive, reflecting on the final value of the feed.

In homemade foods, the only way we can add the correct amount of vitamins and minerals (and also amino acids) is by obtaining the ingredient we call “pre-mix” which are isolated synthesized vitamins and minerals, ready to be used in the feeding formulation.


Overfeeding and Underfeeding: Finding the Balance

Adequate nutrition accounts for the entire fish diet, from the feed ingredients to the amount used in the feed.



Overfeeding is one of the main mistakes made by aquarists, and it can have drastic consequences. 

In addition to obesity and health problems, overfeeding also contributes to rapid water pollution. This occurs either due to leftover food in the aquarium or the excessive excreta amount produced by obese or overfed fish.



Underfeeding is also not rare and can cause problems, resulting in weak and undernourished fish. You can diagnose underfeeding through some physical signs in the fish, such as thin and lethargic, with slow or stunted growth. It can also cause strange behaviors in the fish.


Finding the Balance

To find the perfect diet, we must always use foods suitable for the species in question, feeding the fish several times daily, but in small quantities. Offering small amounts avoids overfeeding and waste, ensuring stable water quality. Offer a quantity that fish will fully consume without resulting in leftovers in the tank.

Use the widest variety of foods possible, and always observe the behavior of the fish; this is the best way to determine the best times and quantities.


Special Dietary Needs for Specific Species

As we have seen, different fish species have specific dietary needs that you must follow to avoid health problems. For all freshwater fish, we must use at least two feed labels for the species, supplementing with live, freeze-dried, or fresh food at least 2 to 3 times a week.

Thinking about a community aquarium, we often have species with different eating habits living together, such as carnivorous Corydoras living with herbivorous plecos and omnivorous guppies on the surface and barbs in mid-water. In this case, we must offer feed that covers all fish.

Continuing in the proposed example, we will offer spirulina tablets along with carnivorous bottom fish wafers. Cories and plecos will consume these pellets. 

A food for omnivorous fish with a tendency towards carnivorism can be used for guppies and barbs, as well as a vegetable food supplement. This way we feed all the fish, leaving no room for nutritional problems. Fish will select preferred foods based on their metabolic hunger (the nutrients the body needs at the moment).


Storage and Preservation of Fish Food

The nutrient content in food is not eternal, being lost little by little, even in vacuum packaging. Ensuring the quality and freshness of food for your tropical freshwater fish is essential. Some techniques help us increase efficiency when using different foods.


Small Size Packaging

Obtaining small package sizes reduces the food’s exposure to air and moisture, keeping it fresh until the food is gone. Large pots will be handled and will be in contact with the atmosphere for longer, resulting in a considerable loss of nutrients. Furthermore, smaller packaging avoids waste.


Storage Instructions

Each type of food, depending on the manufacturer, has specific storage requirements. These requirements include instructions on exposure to temperature, humidity, and light. Strictly follow the guidelines to maintain food quality.


Manufacture and Expiry Date

Always check the date of manufacture or packaging of food, as well as its expiration date. Choose only recently manufactured foods, these are fresh, with the nutritional value closest to that shown on the packaging. In any case, avoid foods close to their expiration date, as they contain very little nutrients.


Old, Moldy, or Expired Food

Under no circumstances use foods with these characteristics. In addition to not having any nutritional content, they can cause problems and illnesses in fish and the aquarium.


Refrigeration for Fresh and Frozen Food

Fresh and frozen foods must be kept according to the manufacturer’s instructions. Generally under cooling in the refrigerator or freezing in the freezer, thus postponing decomposition. Ideally use airtight glass containers to store them, protecting them from external factors.



Properly choosing food for your fish is essential for the health and well-being of the aquarium and its inhabitants. To do this, we must understand the specific nutritional needs of each species, using a range of high-quality foods of different origins.

We must avoid overfeeding and dietary monotony, varying the diet as much as possible and respecting the ideal quantity and frequency for the species. Remember to research the fish you have and adapt the diet to the needs of your tank.

Now that you know everything about feeding freshwater fish in home aquariums, we invite you to share your experiences, tips, and tricks in the comments or our community.