Otocinclus was one of the enormous fish and for beginners in fish keeping, you can use otocinclus fish for reducing the algae from the aquariums. In our aquarium, we use otocinclus for cleaning the algae and it was easy to care for them.

But many beginners don’t know to keep the fish happy and healthy. So sudden changes in the water parameter or feeding may affect the health of fish. So I think it was a good idea to provide a detailed guide for Otocinclus fish.

In this guide, I’ll provide a detailed care guide and some important tips for keeping the fish healthy. So follow till the end to get more care guides.

Quick Stats of Otocinclus

Scientific NameOtocinclus
Common NamesOto, Oto cat, Dwarf Sucking Catfish, Midget Sucker Fish
Ease of keepingEasy
Lifespan5 to 7 years 
Tank size20 gallons and more
Tank typeCommunity of fishes
DietAlgae Cleaner
Temperature72-82°F (22-28°C
Water hardnessno greater than 15dH
Sizeup to 2 in 

Description of Otocinclus Fish


Otocinclus fishes are best for cleaning algae and consider the smallest catfish for aquariums.

It was from a family called Loricarlidae. These types of fish will make significant changes in the aquarium water.

Otocinclus are known by the name of oto, oto catfish, Dwarf Sucking Catfish,

or Midget Sucker Fish. They come in a wide variety of colors and sizes. So you can see some differences between them.

The majority of otocinclus fishes can be found in rivers and they are from South America. Otocinclus can make bigger changes in the water quality and care would be easy. 

The unofficial name of the otocinclus was Dwarf sucker because the sucker shaper mouth was designed for them to feed algae. Otocinlcus fish stay most times at the bottom of the aquarium and they low Driftwood, leaves of live plants, and cucumber.

Lifespan of Otocinclus


These fish can live 3 to 5 years, But you need to provide good water conditions and food for health. Like any animal that has poor condition will decrease its lifespan.

So you need to care for them and provide nutritious feeds for healthy growth.



The appearance looks like cory catfish because they are similar types of fish and I have confused. Otocinclus fish are small fish with narrow bodies, short fins, and sucker mouths shaped for eating the algae.

One of the amazing differences from other catfish species is a row of armor plating across their body that protects the fish from attacking. The hollow space between the stomach gives the low ability to breathe air.

Some of the popular otocinclus species are listed below.

Common Otocinclus

Zebra Otocinclus

Silver Otocinclus

Dwarf Otocinclus

Golden Otocinclus

Otocinclus Care


They are super low-maintenance fishes that require little effort to care for them. But I recommended caring for them because sudden changes in the water temperature will affect their health conditions.

Otocinclus spends more time on the bottom of the tank that’s where algae tend to be. They will clean the algae from the tank, so it will be easier for us to maintain the water quality. All you need is a small filter and an air pump to generate oxygen inside the tank.

They are low-aggression fish, so you can introduce them to any low-aggression fish species. They can get along with any species, but sometimes other fishes will start attacking them.

In the wild, they spend more time at the bottom with so many of them and travel and live in school which makes them safe. I recommended introducing at least 3 pairs of otocinclus for your tank.

Overall, If you are looking for fish that is easy to maintain and provides lots of benefits to your tank then Otocinclus is best for you. 

Without proper care, the fish may die, to know more about why otocinclus dying faster read my article.

What is the Behavior of Otocnclus

As I already stated, Otocinclus was a peaceful fish that gets along with any other species of fish. The docile temperament of fish allows them to stay with any fish, but you can’t introduce it to aggressive species.

These fish don’t become aggressive towards any other fishes because of their nature and small size. Otocinclus fish can swim faster and they are slipper, but an important factor is they need good water conditions to leave.

Overall, Otocinclus was a good fish that helped to maintain the water quality of the aquarium and its docile temperament makes it easier to live with any species.

Otocinclus fish Diet & Food


Otocinclus are vegetarians because they are considered herbivores. Otocinclus mostly eat foods like algae from the aquarium. But many beginners think that they will only eat algae and not provide any other food source for oto’s.

You can feed foods like Zucchini, Lettuce,  and Spinach to your otocinclus. Otocinclus eat algae as a native habitat and live plants provide algae food source, so they spend more time at the bottom of the tank or near the live plants. I have been feeding otocinclus algae wafer for the last three months and found good results.

To maintain the water quality, you can remove excess food from the aquarium after 24 hours. This will make the tank clean and easy to maintain the water quality of the aquarium.

Common Disease

Some of the common diseases of otocinclus fish are Ich, cotton rot, tail rot, body fungus, body slime, eye cloud, Hexamita, dropsy, and velvet.

The best way to keep the otocinclus healthy and keep the stress level is through correct water parameters and feeding time.  Also, you need to keep the otocinclus away from aggressive fishes.

However, the most common disease for otocinclus is malnutrition. Many beginners think otocinclus fishes only eat algae and they don’t feed nutritious food for them.

Water parameters


Water parameters are an important factor for otocinclus fishes. So you need to check the water parameters every week. If there is a change in water parameters, the fish start to show some erratic movements.

Here is the water parameter for otocinclus fish.

  • Water Temperature: 72 – 79 Degrees Fahrenheit.
  • Aquarium pH: 6.8 – 7.5.
  • Provide some live plants for generating oxygen and food sources.
  • Filtration in the aquarium was important for otocinclus to avoid ammonia and nitrites affection.

Use a Canister filter for excellent performance in filtration, you can see the review of the canister filter on my blog.

Tank mates

When you look for a tank mate, you need to select a low-aggression fish. Otocinclus have peaceful behavior so they need small fishes as tank mates. The bigger fish may attack or even eat the otocinclus fish.

Some of the popular fish as tank mates

  • Boraras
  • Cory cats
  • Tetra
  • Rasbora



You can easily breed otocinclus fish in a 20-gallon aquarium. Breeding Otocinclus was similar to the corydoras fishes, You need to select two males and one female for successful breeding.

The female will lay otocinclus eggs on the plant leaves or driftwood. But one major problem is due to fry, The fish will start eating the fry when they give birth, so you need to provide a breeding cage to avoid eating the fry.

How many otocinclus catfish should be kept together?

You need to keep at least 6 Otocinclus in a fish tank. Otocinclus are herbivorous and are schooling fish that help reduce the spreading of algae in fish tanks. You can keep 6 otocinclus for a 10-gallon fish tank and increase the quantity according to the fish tank size.

If you overstock the otocinclus fish in smaller tanks, it will be difficult to breathe and eat food for other fishes. The otocinclus needs to be grouped in small quantities according to the size of the fish tank. Otocinclus needs quality water and water-conditioned tank for healthy living.

How many otocinclus in 10 gallon tank

You should keep at least 6 otocinclus in 10 gallon tank. It was the lowest quantity that you need to maintain in a small fish tank. Otocinclus will not stay alone in the tank because they are schooling fish that love to stay in groups.

The standard size of the 10-gallon aquarium is 20” L x 10” W x 12” H. In this tank, you can keep other fish but don’t overstock fish.

How many otocinclus in 20 gallon tank

In a 20-gallon fish tank, you should keep 10 to 12 otocinclus with proper filtration and live plants. The Otocinclus spends more time on the leaves of the plants. Don’t keep aggressive fishes in the otocinclus tank because otocinclus are peaceful fish and aggressive tank mates will attack otocinclus fish.

The average size of the 20-gallon tank is 24″ x 12″ x 16″. The 20 gallons are better for otocinclus fish because more otocinclus can be kept together. 

How many otocinclus in 30 gallon tank

For a 30-gallon fish tank, you need to keep 15 to 18 otocinclus fish. If otocinclus produce a lot of waste then add sucker mouth fish for cleaning the tank and keep a filtration system for maintaining the water quality.

What is the largest size of Otocinclus?

The Otocinclus can grow up to 2 inches in length with proper care and nutritious foods such as algae wafers, vegetables, etc. Otocinclus flexilis was the largest size 2.1 inches in length. 

What is the Smallest size of Otocinclus?

Tapirape Otocinclus was the smallest size otocinclus with full growth. The size of tapirape otocinclus is 2.4 cm in length.

Do otocinclus eat green Algae?

Otocinclus are herbivorous fish that love to eat algae. Otocinclus are mainly used for reducing the growth of algae in the fish tank. Otocinclus will eat soft green algae and clean the aquarium glasses and leaves of the plants. 

If you feed otocinclus algae wafer then green will start growing because the otocinclus will eat only algae wafer instead of green algae. So you need to monitor the otocinclus behavior and feed only less quantity algae wafers.

Will otocinclus eat Plants

If you care about otocinclus and feed algae wafer then otocinclus will not eat plants. Otocinclus will eat plants when they become hungry. Otocinclus needs proper care to keep them healthy and sudden changes in the water parameters will affect the health condition. Otocinclus may eat decade plants, So you need to remove the decade plants from the fish tank as soon as possible.

Do Otocinclus eat dead leaves?

Otocinclus will eat dead plants or leaves when they become hungry. The otocinclus stays more time on the leaves of the plants to clean the algae and eat small bacteria. You need to remove the dead leaves from the fish tank otherwise otocinclus may eat.

Do Otocinclus need Protein?

Otocinclus needs protein food once a week to encourage the growth and immunity system. For breeding, you can feed high-quality protein food for otocinclus. Don’t overfeed the otocinclus because an uneaten algae wafer will encourage the spreading of algae.

Do Otocinclus need a Separate Tank For Breeding

Otocinclus needs a separate tank for breeding, the otocinclus will not protect the eggs or their fry after laying eggs. The otocinclus will lay eggs and start cleaning the tank by eating algae and staying near the plants.

Do Otocinclus Protect Eggs

Otocinclus will not protect their eggs. You can keep a separate breeding tank for otocinclus and after laying eggs you can keep them in a community tank. The otocinclus fish will not protect their fry. The eggshell will be the first food for otocinclus fry after a few days you can feed small foods to otocinclus fry.

What is the Otocinclus temperature?

You should maintain water temperature between 70-79°F (21-26°C). Sudden changes in the water parameters will affect the health and immunity system of otocinclus fish. You can use the heater to control the water temperature and filter to improve water quality.

Do Otocinclus Clean Tank

Otocinclus catfish will not clean the fish tank, Otocinclus will reduce the algae growth in the fish tank and clean the leaves of live plants. Otocinclus will not eat uneaten foods and fish poops. You can keep a filtration system and weekly tank maintenance for cleaning the fish tank.

What is the price of Common Otocinclus?

The average price of a common otocinclus is $3.50 per unit. The price can vary according to the size of the fish. You need to choose an active otocinclus fish from the store, Otocinclus are mainly found in river basins so sudden changes in the water parameters affect the immunity system, and the fish will be active and stay more time in one place.

Do Otocinclus Eat Fish

Otocinclus will not eat or attack any fish. Otocinclus are peaceful fish that can be suitable for any community tank with low-aggression fish. Otocinclus are herbivorous fish and they eat leaves and algae of the fish tank.

Do Otocinclus Eat Shrimps

Otocinclus will not eat any fish because they are herbivorous. Otocinclus are suitable for shrimps’ tank mates because they will not attack or eat shrimps. 


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