6 Easy Foods To Feed Your Otocinclus So They Thrive!

Otocinclus catfish are a popular addition to many freshwater aquariums due to their small size, peaceful nature, and impressive algae-eating capabilities. These diligent cleaners can be a valuable asset to an aquarium’s ecosystem, but proper care and feeding are essential to ensure their well-being and longevity.

In this article, we will explore the essential dietary needs of otocinclus catfish and provide suggestions for maintaining a healthy, well-balanced diet.

The primary food source for otocinclus catfish is algae and biofilm that grow naturally in a fish tank. Their voracious appetite for these substances helps keep the aquarium clean and well-balanced.

However, depending on the tank conditions and the availability of algae, it might not be enough to sustain a thriving otocinclus population as they can quickly consume all of the algae in a tank. This is why providing a supplemental diet is necessary to support the health and growth of these catfish.

In addition to their natural diet, otocinclus catfish enjoy a variety of vegetables and specialized fish food. Algae wafers and sinking vegetable flakes are popular choices for many aquarists, along with vegetables like cucumber, zucchini, spinach, and kale.

Soft Green Algae

what to feed otocinclus

Otocinclus are well-known for their love of constantly grazing on soft green algae, which can be found covering various surfaces in your aquarium, such as the substrate, decorations, plants, and glass.

This type of algae serves as a natural food source for your Otocinclus and will naturally grow within their tank at no additional cost.

Many aquarists choose to add a group of at least six Otocinclus to their tank specifically to help control the growth of soft green algae. These small fish can be quite efficient in their algae-consuming endeavors, swiftly working their way through the available supply. As a result, it’s essential to remember that once the bulk of the soft green algae has been consumed, it’s crucial to supplement your Otocinclus’ diet accordingly.

In providing an environment conducive to soft green algae growth, your Otocinclus will have access to their preferred, natural food source. This will not only benefit the overall health and well-being of your fish but also contribute to the cleanliness and maintenance of your aquarium. However, striking a balance between encouraging algae growth and ensuring your Otocinclus have access to appropriate supplemental food sources once the soft green algae have been depleted is key for their long-term health and happiness.


An Otocinclus On A Leaf
An Otocinclus On A Leaf

Diatoms are microscopic algae that can become a natural food source for your Otocinclus catfish. They often grow in aquariums, providing a free and nutritious option for these fish. Diatoms are usually brownish in color and can be found on various surfaces within your tank, such as the glass, decorations, or substrate.

As a reliable food source, diatoms can help support your Otocinclus’ health, since these algae consumeers primarily thrive on this resource. However, it’s essential to recognize that diatoms typically have a limited growth period within an aquarium.

During the first few weeks of setting up your aquarium, diatom growth can be rapid, providing a rich food source for your Otocinclus. Unfortunately, after this initial bloom, the diatom growth rate tends to decline drastically. This decline is due to the maturing of the aquarium, leading to a more balanced ecosystem with fewer diatoms as other microorganisms gain a foothold in the tank.

As the growth of diatoms decreases, you will need to consider supplementing your Otocinclus’ diet with other food sources. Algae wafers, vegetables, and catfish pellets are all viable options for maintaining a well-rounded diet for your fish.

In summary, while diatoms serve as a natural and nutritious food source for your Otocinclus, it is crucial to monitor their growth rate and supplement their diet with other options as needed. This approach will ensure that your fish receive the proper nutrition they need to thrive in your aquarium.

Blanched Vegetables

An Otocinclus Eating Cucumber
An Otocinclus Eating Cucumber

One commonly food source for Otocinclus catfish in aquariums is blanched vegetables. Nutrient-rich and easily digestible, these vegetables are an excellent supplement to the algae in your fish tank. Some of the most popular blanched vegetables for feeding Otocinclus include zucchini, spinach, cucumber, lettuce, peas, and green beans.

Among these, zucchini and cucumber tend to be the more favored choices.

Blanching the vegetables is a simple process that softens the food, making it easier for your Otocinclus to consume and digest. To blanch vegetables, follow these steps:

  1. Cut The Vegetables Into Small, Manageable Pieces, and remove the skin of the vegetable if needed due to chemicals and pesticides often being used.
  2. Boil A Pot Of Water.
  3. Place The Cut Vegetables In The Boiling Water For A Short Period, Typically 30 Seconds To 2 Minutes Depending On The Vegetable’s Thickness.
  4. Remove The Vegetables From The Boiling Water And Immediately Place Them In A Bowl Of Ice Water To Stop The Cooking Process.
  5. Once Cooled, Pat Dry The Vegetables And Place Them In Your Aquarium.
How To Blanch Vegetables For Fish, Shrimp, And Snails

When feeding blanched vegetables to your Otocinclus, it is important to manage the amount of food in the aquarium. Offer only enough vegetables that your fish can consume in a reasonable time frame. It is advised to remove any remaining blanched vegetables from the fish tank after 24 hours.

This is essential to maintain a healthy environment and avoid disrupting the water parameters.

In summary, providing Otocinclus with blanched vegetables such as zucchini, spinach, cucumber, lettuce, peas, and green beans can significantly contribute to their health and well-being. By following the proper blanching process and removing leftover vegetables in a timely manner, you can ensure an optimal and balanced diet for these algae-eating fish.

Algae Wafers

Algae Wafers

Algae wafers are a popular choice among aquarium enthusiasts when feeding their Otocinclus but not all algae wafers are created equally. In this section, we will discuss the importance of quality when choosing algae wafers and recommend a top-rated brand that meets the dietary needs of Otocinclus.

It is crucial to select high-quality algae wafers for your Otocinclus, as they can be picky eaters. Many budget-friendly algae wafers contain wheat and other grains that may be attractive to other fish but are often ignored by Otocinclus.

These fillers provide limited nutritional value to these algae-eating fish and can often put your Otocinclus off those particular algae wafers with many Otocinclus refusing to eat them.

Hikari Algae Wafers are an excellent choice for feeding Otocinclus. They are grain-free, ensuring a more natural and nutritious diet for your fish. These wafers also break up easily, allowing the Otocinclus to consume them without any issues. Many aquarium enthusiasts have observed that Otocinclus catfish seem to enjoy eating Hikari Algae Wafers, making them a reliable choice for maintaining the health and happiness of your fish.

In addition to algae wafers, it is beneficial to provide a variety of other food sources for your Otocinclus, such as vegetables and sinking vegetable pellets. Feeding your Otocinclus a balanced diet will ensure they receive the proper nutrients they need to thrive in their tank environment.

By selecting high-quality algae wafers like Hikari Algae Wafers and providing a variety of food sources, you can ensure that your Otocinclus catfish receive the proper nutrition they need to maintain their health and well-being.

Indian Almond Leaves

An Otocinclus grazing on a Indian Almond Leaf
An Otocinclus grazing on a Indian Almond Leaf

Otocinclus are known for their herbivorous diet, which mainly consists of algae and biofilm. Although they don’t directly consume Indian almond leaves, they are attracted to these leaves due to the biofilm and algae that grow on them at a surprisingly rapid pace.

Indian almond leaves release tannins and beneficial substances into the water, providing an excellent surface for biofilm and algae to flourish. This makes them an ideal addition to an Otocinclus habitat as a natural, indirect food source. Furthermore, the decomposition of Indian almond leaves enhances the biofilm’s growth, making it even more accessible to the Otocinclus.

An Otocinclus Grazing On A Leaf

Adding Indian almond leaves to an aquarium not only benefits the fish but also helps mimic their natural environment by providing shade, shelter, and an enrichment element. We usually try to have at least one Indian almond leaf in our aquarium at all times as our Otocinclus, shrimp, and snails all seem to enjoy grazing on them.

As the Otocinclus graze on the biofilm and algae present on the Indian almond leaves, they will also assist in maintaining a cleaner and healthier environment within the tank. This, along with the aforementioned benefits of adding Indian almond leaves to an aquarium, makes them an attractive option for fish keepers looking to enhance the living conditions of their Otocinclus population.



Spirulina is a highly nutritious, natural algae that serves as a beneficial food source for Otocinclus. It is available in various forms, such as powdered and pelleted, making it a versatile and convenient option for feeding these algae-eating fish.

Spirulina is often included in regular algae wafers but it is usually considered to be a higher grade of algae and pure spirulina tablets are a very popular food option for Otocinclus.

Powdered spirulina is an excellent choice for those looking to provide a diverse diet for their Otocinclus. The fine texture allows it to easily adhere to surfaces and spread throughout the tank, ensuring that the fish have ample opportunities to graze on the nutritious algae. Moreover, the powder can be mixed with other foods such as vegetables and algae wafers, creating a more balanced and wholesome meal for the Otocinclus.

Pelleted spirulina offers another feeding option for Otocinclus. These pellets can easily sink to the bottom of the tank, where the fish tend to spend most of their time. However, it is essential to ensure that the pellets are free of grain additives, as some Otocinclus may refuse to eat them if they contain such ingredients. To achieve this, it is advisable to carefully read the labels and opt for high-quality brands that prioritize natural and healthy ingredients for fish.

In summary, spirulina is a valuable food source for Otocinclus, offering essential nutrients and promoting overall health. Both powdered and pelleted forms of spirulina can be utilized, based on individual preferences and the needs of the Otocinclus community. Nevertheless, it is crucial to avoid pellets with grain additives, as they may be less appealing to these finicky eaters. By incorporating spirulina into the diet of Otocinclus, aquarists can ensure that their fish receive optimal nourishment and thrive in their aquatic environment.

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