Otocinclus – A Complete Guide – Care, Diet, Facts

When thinking of an aquarium there are a few different things that can come to mind.

You may be the person with that glass half empty personality; and that’s okay. If you’re the type of person that always thinks about the time involved and the con’s to be an aquarium owner.

Do you think about the amount of time it takes to maintain the tank?

With the right fish in your aquarium your tank will be low maintenance and your fish can even clean your tank for you.

The Otocinclus fish not only add visual appeal to the tank, but they play a role as janitors in the tank.

The feed off of algae; this is the stuff that builds up on a tank.

Otocinclus are a must have fish for any community tank!


Getting to Know Otocinclus

Although, Otocinclus is the given name these fish are more often referred to as an Oto Catfish or a Dwarf Sucking Catfish.

Oto Catfish are often overlooked in a community tank because they aren’t going to be the biggest nor the brightest thing in the tank. These fish often have an appealing coloration or specific characteristics that make them just as beautiful as the next fish.

Although, the biggest reason for their presence in an aquarium is because they are algae eater. Algae eaters spend their day searching the tank for “amuck.” Being herbivores, their only source of nutrition is the build up on your tank.

There are 19 different species of Otocinclus found in the wild today. Although, only a few are found in freshwater aquariums today.

Typical Behavior/ Habitat in The Wild

If you were to go searching for these out in the wild you would find these fish somewhere on the edge of a small to medium sized river or lake. Where you find one you will find at least 4 more because this is a schooling fish.

Oto Catfish are found across South America.

Otocinclus fish are fish are peacekeeping fish that have no form of aggression. Being a bottom feeder, these fish are found at the bottom of the food chain in the wild.

These fish often stay stressed, never knowing when another fish is going to swallow them make the best of us shake.

These fish rarely scurry but when they do it’s because the felt endangered and had to flee.

You will rarely see this fish off the bottom of the tank unless it’s on a plant or decoration with algae build up. If there are no algae this fish does not see any reasoning in being there.


Just like any other breed of fish each different species has different characteristics that separate them from the rest of their family.

Oto Catfish are fish are bony fish, with long flat bodies and big eyes. Their eyes help them find algae; bottom feeders are often feeding in the dark in their natural habitats.

Otocinclus have strong mouths used to bring in algae that is stuck on the surfaces of its surrounding.

These fish never get large, only growing to roughly 2 inches in size. This gives them the advantage over other breeds of sucker fish because they can be placed in any size tank.

Otocinclus are one of the select breeds where the females are longer and fatter than the males.

Although, these fish aren’t all about only added to tanks for algae purposes. They are also just a beautiful fish with alluring features. Each and every type of Otocinclus draws in hobbyist due to some feature that they hold.

Most Common Aquarium Breeds of Otocinclus Fish

Although, there are around 19 different species of Otocinclus a majority of them aren’t going to be found in your local pet/fish store.

When going on the hunt for an Oto Catfish to relocate into your tank you are going to find:

Common Otocinclus (Otocinclus Vittatus)

The Common Otocinclus got its name for the exact that. It is the most commonly caught, sold, and distributed Otocinclus of the family.

These fish have a brown spotted upper half running to a solid brown stripe down the middle and a white underbelly.

The Common Otocinclus are the main reason that all the species of the breed are so well known and housed in tanks across the world.

These fish are not only beautiful but are the janitors of the tanks often times cleaning more algae in a day than can be produced in five.

Due to these being schooling fish these fish often have to be fed some other source of algae to keep from starving and dying.

Being 2 inches or smaller these fish live their lives being at the very bottom of the food chain. Between being small enough to swallow whole and vegetarians they get eaten before they will kill to survive.

Common Otocinclus have adapted over the years to having to protect their selves from predators by learning how to swim fast to keep from larger slower fish in their atmosphere.

Golden Oto (Otocinclus Affinis)

Golden Oto’s are an average sized species of the Otocinclus breed. These fish have a “golden” brown back with a cream stomach and a black stripe down the side of the torso.

Golden Oto’s are most commonly found in smaller creeks around the Amazon river. Which are flooded with plant life.

These fish need to be in a heavily planted aquarium to mimic their natural habitat. Without this they can become stressed and begin to die off due to high stress levels.

Golden Oto’s are more of an evening and night dweller, doing most of their eating and movement throughout the night. Staying hidden and away from predators during the day.

With that being said ensure that your Aquarium is also has plenty of hiding spots or enclosed areas for these fish to hide and feel safe.

This species is not the easiest to care for. Golden Oto’s are sensitive to water levels and need a specific number of components in the water in order to flourish.

You will have to have the correct number of nitrates and ammonia in the water. The water will need to have a set Ph that correlates with the fish’s needs, along with a specific water hardness.

On top of the correct water temperature that allows the fish to thrive.

Females are slightly larger than males. Keep an eye out at the bottom of the tank along the plants to ensure they haven’t laid eggs in your tank.

Zebra Otocinclus (Otocinclus Cocama)

The notorious Zebra Otocinclus got their names for looking as is sounds.

These fish have brown stripes down the top of its back running to its tail fin. With a clear tail fin with a single black stripe in the middle.

Zebra Otocinclus are one of the smallest species in family. Mature females will grow to be a little greater than 1.5 inches. While males will stay at or under 1.5 inches.

Don’t underestimate their algae eating abilities by their size. These fish will make even the worst tanks spotless in little to no time.

Due to their high appetite it’s not uncommon for people to have to put algae tablets or dried leaf litter in the tank to ensure these fish will have enough to eat.

Originating from waterways in Peru.

These fish live-in fast-moving water with a high current. So, they should be placed in a tank with a fast-moving filtration system.

Due to the amount of current and commotion that these fish endure in the wild they will do best in a large tank with plenty of space to move around in.

These fish are found where there is plants and grass growing in the water. Zebra Otocinclus are usually found near the surface of the water around the plant-life.

The Zebra Otocinclus is the second runner up for having the greatest number of teeth in the family; just under the Otocinclus Batmani.

Due to their small size and unaggressive personality they do not do well in a community tank with large and assertive fish. These fish will get stressed out due to their surroundings and begin to die off.

Dwarf Oto (Otocinclus Macrospius)

If you take the markings of a Golden Oto and mix them with the markings of a Zebra Otocinclus you will get the picture of a Dwarf Oto.

Dwarf Oto’s have the cream belly with black line across the abdomen as the Golden Oto’s have. With a section of stripes across the top half of the body as the Zebra Otocinclus have across their body. Running into a transparent tail fin with two black stripes; rather than the one that Zebra Otocinclus carry.

In the wild these fish travel by the thousands in a school to keep them having a sense of security.

Although, in tanks they need a school of at least 3 fish. The more the better.

This fish does great in any size community tank with any sized if.

Dwarf Oto’s have a peaceful personality and will not harm other fish without good reasoning.

Some people have noticed their Dwarf Oto eating the slime of other fish in the tank leaving open sores in place of the slime and scales.

They do this with no aggression. The reasoning behind this is because they are beginning to hit near starvation and are going to what closest resembles algae in the tank.

So, if you begin noticing this try placing algae tablets into the tank to provide more food for the Oto’s.

If the pet shops, try to tell you that these fish have a high mortality rate it is due to their own lack of knowledge. These fish are a hardy, easy to care for fish and do not die easily.

If they are dying off easily it’s because they are not leaving enough food in the tanks and they are starving.

People tend to under compensate, forgetting that these fish eat all day long, only breaking to sleep.

Dwarf Oto’s need some sort of plants in order to thrive in a tank.

Silver Oto’s (Otocinclus Vestitus)

Silver Oto’s upper half looks more silver than the tan of most other Oto fish. Coming to a black stripe and a white belly.

These beauties will add that glimpse of sparkle that other darker relatives will not.

Silver Oto’s are a hardy fish that can thrive in any size tank.

These fish need plants and structures to hide in for both security and feeding purposes.

You will rarely see these fish move from place to place, due to the fact that they conserve energy moving inches at a time to allow them to get ever piece of algae amongst the aquarium.

Silver Oto’s are a great addition to any size tank.

Silver Oto’s get up to nearly 2 inches, males can and will often stay a little smaller.


Although there are other types of Otocinclus these are going to be most often the ones sold to you from stores.

You may be able to find rare gems of Otocinclus that are not mentioned above; just make sure to do your research. Every fish has specific needs and you want to ensure they are met.

Habitat and Tank Conditions

These fish are most commonly found in rivers and streams across South America. They feed near the edges or in shallow areas around plants and grasses.

Otocinclus use their powerful suckers and latch onto the substrates or rocks around them and feed in that small area until there is nothing left in that space.

Moving down the area slowly until the area is clean of algae.

Being in South Africa these fish are warm water dwellers. Most commonly these fish are going to reside in slow moving waters that are oxygen rich; because of the abundance in plant-life in and around the water.

Otocinclus are used to Ph neutral waterways for the most part; keep in mind there are a few fish in the family that break every common clause.

These fish are happy in water that’s temperatures vary from 72°F to 79°F. Along with a Ph of 6.8 to 7.5.

As I mentioned for all of the breeds these fish need a planted aquarium, although, there is such thing as too much.

These fish need plenty of room to maneuver and scurry when they feel like it. Even though they rarely will scurry unless they feel threatened in some way.

Some of the species are hardy while others are sensitive to water conditions just know which is different from which. To prevent sudden deaths in your tank

Tank Setup

While the top and middle sections of your tank will mostly be determined by your Otocinclus aquarium mates the bottom of the tank is all about making these fish feel at home.

When placing your base choose some sort of fine and soft substrate over something dense or coarse because this can rub on your Otocinclus and damage or break open the skin and cause them to get sick and die.

Use rocks or decorations to create caves or hidden areas for your fish to hide in to have a sense of shelter for security. Oto’s like to hide and find shelter when they are feeling vulnerable or threatened.

Plant some type of vegetation and plants. This will one create more places for the fish to hide. Two create a sense of home, these fish camp near plants in the wild. Three this will supply the oxygen these fish need in their water.

The plants shelter and rocks add more places for algae to grow, supplying them with a larger source of food to feed on.

The tank needs to be free of ammonia and nitrates at all times.

Doing a water change every 1.5-2 weeks.

These fish need 1.5-2 gallons of water per fish.

Otocinclus Tank Mates

Otocinclus are peaceful fish that have no aggression whatsoever. Not even when it comes to protecting themselves.

So, when choosing tank mates this needs to be heavy on your mind. This fish can and will not protect themselves from aggressive fish; and due to their size, they will be targeted first.

For most Otocinclus fish they can be in a community tank with a wide variation of other types of fish and do well.

The two main fish that people enjoy in community tanks that need to be avoided are Oscars and Cinclids. They are known for their aggression and will quickly take a bite on your Oto fish.

Most other pet store fish can and will get along and tie in nicely with your fish. Just watch carefully for tags of aggression at your local pet store.

What to Feed Otocinclus

These fish are 100% herbivores. So, they aren’t going to eat your fish food, flakes, or anything of that matter.

Instead allow them to first eat their natural source of food, your tanks algae build up.

Once that is gone, they will eat algae wafers you purchase in the fish food isle. Dissolving over 1-2 days.

Although, past the natural algae the best source of food, is veggies straight out of your kitchen. Chopped very finely for your Otocinclus to eat. Green veggies are the best!

Keep in mind that after 24 hours the left-over food that remained should be removed from your tank.

Otocinclus Care Guide

Otocinclus are often known to be a hardy fish. Although, just as other fish these can be known as a sensitive fish.

Especially when it comes to their water conditions.

If the fish are going to have any problems with your tank its going to happen very quickly after they are first placed into your tank.

I advise that you quarantine your fish alone for two weeks before placing them with your other fish. Just to ensure they don’t have a disease that can spread throughout your whole tank.

These fish aren’t known for carrying any diseases but can get parasite and fungal problems. For one example they can get Ich.

Just keep an eye out for a sick looking fish and isolate them as quick as possible.

Food and water conditions are the two main reasons for a fish to catch a disease.

Breeding Otocinclus

Oto’s are not easy to breed, because they will want everything to be perfect or they will not bother.

So unlike other breeds of fish they are hard to get breed in captivity.

They prefer if the water temperatures are higher when they are mating. So, bringing the temperature at least a couple degrees above their norm.

In the wild a rise in temperature is a natural que of mating season.

After playing a game of cat and mouse the male will swim around the tank fertilizing the female’s eggs.

If properly done and all conditions were fit for both male and female a few short days later the fry come out and begin performing as their mother and father.

Are Otocinclus For You?

These algae eaters are perfect for any community tank with non-aggressive fish. Adding appeal and cleaning up these fish make any aquarium that much easier to maintain.

Being a schooling fish, these fish need at least 3 or more other fish in the tank if not more. The more in the school the happier, healthier and safer the fish feel.

Understanding and knowing the exact species in the family is crucial in order to understand the needs of the fish.

Ensuring your tank is set up and well maintained will keep your fish from dying shortly after transfer.

The number one problem people have with these fish are starving them. Always keep up with the food they have eaten and keep in mind these fish never stop eating.

No matter the species of Otocinclus you buy you will not be let down.

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