Otocinclus Catfish: Ultimate Guide (Care, Diet, Breeding, & More)

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Written By Matt Stevens

Hi, I'm Matt! I've been obsessed with fishkeeping for over 15 years now and created this site to share my knowledge with others.

While there are several species of catfish out there, our most favorite species is the incredibly beautiful and striking Otocinclus Catfish. They are a great addition to your tank, and they also help keep the aquarium clean by eating up the algae growing in the water.

These fish are peaceful and friendly species, and they can be kept in the tank with a wide range of other species. You won’t have to break up any fights between them and other species, which is a relief for aquarium owners.

Another great thing about Otocinclus Catfish is that they are really easy to care for. They are among the most low-maintenance species in the aquarium community. Not to mention, they are lovely to look at.

If you want to keep them in your tank, there is no better way to prepare than by reading this guide, which covers all the care guidelines and requirements. It will help you find out about their habitat, water requirements, diet, tank mates, breeding, and much more.

Species Summary

Otocinclus Catfish are a small and beautiful species of freshwater catfish, and they are classified into 19 different species of the Loricariidae family. Interestingly, their scientific name is simply Otocinclus, so you won’t have any trouble remembering this.

Some of the nicknames that these fish are called by include Otos and dwarf suckers, owing to their algae-eating capabilities. They are also instrumental in keeping the water quality maintained in your aquarium.

Life Span3-5 years
Color FormVarious
Care levelEasy
CompatibilityPeaceful species
Size1-2 inches
Tank SetupFreshwater with sandy substrate and caves
Minimum Tank Size10 Gallons

These catfish come in a huge variety of sizes, colors, and appearances. Like several other species of catfish, these are also native to South America, mostly in countries like Argentina and Venezuela. Generally, these fish are found in smaller rivers, unlike other catfish that love large water bodies and streams.

Otocinclus Catfish are wonderful additions to any freshwater aquarium, and even beginners can handle the task of taking care of them daily. All you need is our guide and the willingness to keep them in your aquarium, and you are good to go.

According to experts, you should opt for fatter fish because the latter are prone to starvation, and they don’t recover from it at all. Apart from this, you should consider the ones that are healthy with bright eyes and a larger bodies. Make sure that the fish aren’t fighting to swim or breathe because you won’t be able to heal them through any method.


Otocinclus Catfish can live between 3 to 5 years in captivity, especially if you maintain the tank and water conditions, and also provide them with everything they need to stay healthy and happy.

like any other creature, these catfish can suffer greatly from poor water quality or tank conditions, and it will also shorten their lifespan.


As mentioned above, Otocinclus Catfish come in a variety of sizes, patterns, and colors. Generally, these fish have large mouths that suck on algae and live plants. Whichever color or pattern they may have, you would always find them strikingly beautiful.

Commonly, all of the species of Otos have a brown stripe that stretches from their head to their tail. Like other freshwater catfish from the Loricariidae family, they also have armor plating on their bodies, which can protect them from other fish that are aggressive or excitable. The plating also protects their body against rough and rocky surfaces.

While eating the algae in the wild, the armor plating also protects them from scratching their bodies against the river bottom.


Most of the species of Otocinclus Catfish are small in size, and even the adults don’t measure more than 2 inches in length. Due to this, they are also called freshwater nano fish. You might also find Otos that measure only 1 inch in length.

Generally, they have a cylindrical-shaped body, and the body becomes narrower at the caudal fin and head.

Types of Otocinclus Catfish

There are several different types of Otocinclus Catfish, and they are incredibly peaceful. This makes them the perfect addition to community aquariums, especially since they have a non-aggressive temperament.

Some of the popular types of fish include:

Common Otocinclus

These species have the scientific name Otocinclus vittatus. They contain strong brown or black lines stretching the entire length of their body, as well as their caudal fin. Their upper body is almost entirely brown, while their lower body is white. Their other fins are usually transparent in color.

Zebra Otocinclus

These catfish have the scientific name Otocinclus cocama. As the name suggests, they have white and black vertical stripes going from the back of their head all the way to the caudal fin. They also have horizontal stripes across their head. You may also see them being referred to as Tiger Otos.

Golden Oto

This species is known to be one of the smallest catfish out there, and they are similar the Common Otocinclus as well. Known as the Otocinclus affinis, the brown color of their stripes is closer to golden, which is how they get their name.

Silver Oto

This species is called the Otocinclus vestitus, and they also feature a vertical stripe, as many others do. Their brown colored stripes are so light that they actually resemble silver. Other than that, they are indistinguishable from Common Otocinclus.

Dwarf Oto

Known as the Otocinclus macrospilus, Dwarf Otocinclus look a lot like the Common Otocinclus, and they even have dark brown stripes on their bodies. However, their caudal fin is different. Their fin has a transparent appearance, and they also have a colored blob on their tail.

Otocinclus Catfish Care

Generally, the care guidelines and requirements for Otocinclus Catfish are really simple to understand and follow, which is why you don’t require any extra effort to keep them healthy and happy.

Their low-maintenance care is something that makes them highly sought after among aquarium owners.

These fish spend most of their time at the bottom of the aquarium because they find enough algae to feed off of in the substrate. They also adapt well to changes in water conditions and environment, better than other types of smaller fish.

Plus, they are quite friendly and get along well with other freshwater species. In their natural habitat, they have schooling characteristics and tend to feel much safer this way. So, if you are looking for beautiful freshwater fish that are easy to take care of, these are the perfect pick.

With that said, let’s have a look at more detailed and specific care requirements for Otocinclus Catfish.

Tank Size

The minimum tank size for Otocinclus Catfish should be around 10 gallons. While this may seem smaller to you, you would be surprised to know that you can easily house a group of 4-6 Otos in a 10-gallon tank only!

Other than this, these fish should also have plants, and natural lighting should also be an integral part of their habitat in captivity.

If you are looking to keep them with other species of fish, you may want to consider the minimum tank size for the other species as well. In any case, a minimum of 20 gallons would be ideal, and you will have to increase the tank by 5-10 gallons for every 3-4 Otos that you add to the aquarium.

Water Parameters

In their natural habitat in South American waters, Otocinclus Catfish suck on the growing algae from rocks, gravel, and other surfaces found at the bottom of the river. Moreover, they stay and move around in groups since they are quite small in size and need safety in order to eliminate stress.

Just like every other fish, the only way to keep your Otos happy in captivity is to replicate the natural environment that they are used to. For instance, these fish are used to warmer waters, so you should set the water temperature between 72°F to 79°F.

Since they also thrive in neutral waters, you should set the pH levels between 6.8 and 7.5. Moreover, the water hardness should be kept below 15dH, because these fish thrive in soft waters.

Although Otos keep their tanks clean and clear by munching on algae, you will still need to change the water partially every one or two weeks. This would also keep the nitrate and ammonia levels at bay, and it would maintain a healthy living environment for your Otocinclus Catfish.

What to Put in Their Tank?

Since Otocinclus Catfish are bottom dwellers, you should keep a soft and sandy substrate in the aquarium and prevent keeping any accessories with rough surfaces since it could damage their skin as they scavenge for algae.

If their body gets scratched, it will increase the likelihood of infections and other diseases, which is why you should ensure that the surface isn’t rocky or rough. Even though these fish have armor plating on their bellies, you shouldn’t rely on their protection.

After the substrate, you can add a variety of decorative accessories in the aquarium, so they can hide among them when they need to rest. You can also add larger rocks that serve as hiding spots and caves for these fish.

When it comes to Otocinclus Catfish, you don’t need to add any air pump. Just add a standard aquarium pump, as well as standard lighting.

Common Diseases

Generally, Otocinclus Catfish aren’t prone to any specific diseases, but they may suffer from parasitic or fungal infections that freshwater fish are prone to.

Ich is one of the most common diseases that Otos suffer from, and it is also known as white spot disease. If you notice the presence of small white spots on their bodies, you would need to check the water quality and tank conditions.

If your fish aren’t eating properly or have stopped moving around too much, they may be ill or infected with a disease. Make sure to address their illnesses proactively. Otherwise, things can go bad.

What Do Otocinclus Catfish Eat?

Otos are known to be herbivores, which means that they thrive on vegetation. You already know that they like to eat algae. Apart from that, you can also add live plants to the tank since Otos need them to fulfill their nutritional requirements.

Not only that, but the fish can also hide among the plants when they are tired or stressed.

You can also feed them commercial fish food, such as algae wafers that are commonly found in pet stores. Alternatively, if you have vegetables like spinach, lettuce, zucchini, and others in your kitchen, you can feed these to your Otos. You can cut them up into smaller pieces for your fish and give it to them a few times every week.

You also need to ensure that all food sinks to the bottom of the tank since Otos don’t swim up to eat. Moreover, you will also have to remove any uneaten food from the aquarium because it can start rotting, which can contaminate the aquarium.

Behavior & Temperament

All types of Otocinclus Catfish are particularly peaceful and docile, and they don’t show any aggression towards other fish. However, they may be intimidated or threatened by larger fish.

They can also swim very fast and tend to zoom away quickly if they are stressed or scared. Therefore, it is important to add hiding places that they can scamper off to.

When you are placing them in your tank, make sure to get at least 4 or 5 of them together since they like to stay and travel in schools.

Otocinclus Catfish Tank Mates

Otocinclus Catfish can cohabitate the tank with several other species of fish since they have a pleasant and peaceful temperament. Therefore, you should keep them away from fish that are aggressive in nature. You should also avoid pairing them with fish that have a mouth wide enough to gulp down the Otos in one bite.

Let’s have a look at some of the most suitable tank mates for Otocinclus Catfish:

You can also add invertebrates to the aquarium, such as freshwater snails and shrimps.


Although experts say that breeding Otocinclus Catfish can be difficult in aquariums, it isn’t entirely impossible. However, you should keep the tank and water conditions well-maintained and clean if you want to breed Otos.

To prepare your Otos for mating, raise the water temperature by 1 or 2 degrees only, as this signals them that the conditions are ripe for breeding.

When the males are willing to mate, they will chase the female species. When the female is ready, she lays eggs on the aquarium floor, and the male fertilizes them.

When the breeding process is complete, the eggs will start to hatch, and you will notice small fry swimming close to the bottom. They will feed on algae, so you won’t have to provide them with any extra food.

Final Thoughts

Otocinclus Catfish are beautiful and active species of freshwater fish, and they are also beneficial for your tank since they get rid of most of the algae in the tank. They are easier to take care of and also get along well with other species in the tank.

Moreover, they are delightful to watch in the tank, and if you are looking to bring them to your home aquarium, don’t forget to refer to our guide whenever you need help in caring for them.