Otocinclus Catfish Care {A Complete Guide With Pictures}

This is one of my all time favorite fish in my tank. Let me explain why.

An Otocinclus catfish care guide is something I prepared with pleasure because I want you to enjoy this creature as much as I do.

In this article, you will find out all the basic, quirky and interesting facts you need to begin taking care of Otocinclus catfish.

Otocinclus Catfish Care

The Otocinclus catfish are very peaceful fish as you can put them in varieties of freshwater community aquariums. They are scavenger fish that mainly feed on algae as their natural food, making their feeding easy.

They are excellent for novices because they require little maintenance and don’t put any burden on you as their ecosystem manager.

Otocinclus Catfish

Quick Facts

Temperament : Peaceful
Freshwater / Saltwater Fish : Freshwater
Care Level : Easy
Colour : Several colours, with a brown stripe along their body
Diet : Fish Flakes, Blood Worm, Java Moss
Adult Size : 1-2 inches
Lifespan : 3-5 years
Water Temperature : 72-790F
Water Ph : 6.8-7.5
Tank Size : Min 5 Gallon


Otocinclus catfish are small size fish that can grow up to 1 to 2 inches. They are very easy to care for as they do not require much attention and they are flexible with requirements for their living. The catfish are scavengers; most of their diet is algae making it easier to feed them.

Otocinclus catfish come in different colours. Most of them have a brown stripe that runs along their body. They are very interesting to watch as they possess fascinating features.

Otocinclus Behavior

Otocinclus catfish are very peaceful as they:

  • possess no aggressive behaviour
  • are very delicate fish
  • have little or no means of protecting themselves
  • are active fish swimming peacefully.

The fish also create high interaction with other fish in the tank, provided they are compatible. Also, they react to changes in their environment easily.


The Otocinclus catfish are small fish as they rarely grow to pass 2 inches, with the largest species growing to a size of 2.2 inches. Also, they have:

  • a cylindrical body shape that narrows towards the caudal fin and head. 
  • strong mouths that help them latch onto surfaces.
  • rows of armor plating on their body that protects them from rough surfaces and other fishes.
  • several colors.

Most of them have a brown stripe that runs along their body. Female Otocinclus catfish have broader and larger body shapes than males.

Otocinclus catfish appearance

What Is The Life Span of Otocinclus?

The Otocinclus catfish can live up to 3 to 5 years of age and will live longer than compared to other fishes. They live less in the wild than they do in captivity.

Their lifespan depends on how much you take care of them and provide their requirements. You can guarantee a long lifespan of your Otocinclus catfish if you take care of it and provide a healthy living environment for it.

How Big Do Otocinclus Catfish Get?

The size of your Otocinclus fish depends on how good and healthy you fed them. It also depends on how well you provide their tank and water requirements. However, no matter how much you feed them, they have a maximum size they can reach.

Otocinclus catfish grow to:

  • 1 to 2 inches
  • up to 2.2 inches

The largest of the Otocinclus catfish grows to a size of 2.2 inches.

How Can You Tell if an Otocinclus Catfish Is Male or Female?

It might not be easy to differentiate between a male and female Otocinclus catfish. The most common way to differentiate the male and female is their body shape.

  • Females usually have a larger and broader body shape around the midsection.

You can notice this when you view them from above.  You can also differentiate the male from the female during breeding season as you will notice the male Otocinclus catfish chasing after the female.

Compatible Otocinclus Tank Mates

The Otocinclus catfish are very peaceful and non-aggressive. This behaviour makes them attract a lot of tankmates and makes them suitable for community tanks.

  • These fish have little or no means to protect themselves from fish attacks and are fragile.
  • They have a small size, which gives some large fishes the ability to eat them.
  • Although they are fast swimmers, other fishes can also be fast enough to feed on them.

These reasons are why you have to consider their tankmates before adding them to the tank.

Compatible tank mates for Otocinclus catfish include:

  • Angelfish.
  • Dwarf gouramis.
  • Zebra loachesOtocinclus catfish tank mates

Water Parameters For Otocinclus

You must consider the water conditions of a tank or community tank before adding your Otocinclus catfish. Otocinclus catfish are very fragile, and they respond greatly to environmental changes.

If the water condition does not suit their body, it can deplete their health, or worse, cause them to die. Providing good water conditions for the fish does ensure not only its healthy living but also the good health of other fish in the tank.

1. Temperature

Otocinclus fish like to stay in cool waters. The water temperature should be from 72 to 79 degrees Fahrenheit. Ensure you maintain this temperature with only a slight allowance for the deviation from the value.

It is recommended to use an aquarium heater to keep the water temperature at the recommended setting. If you are after a heater check out the ones available on amazon

2. PH Level

The pH level of
the water is essential because the wrong pH value can harm your Otocinclus catfish. The fish prefer slightly acidic, slightly alkaline, and neutral waters. The pH value should range from 6.8 to 7.5.

You can monitor your aquariums water using a PH water tester kit available on amazon

3. Oxygen level

As with most fish it is important for these fish to live in well oxygenated water, For this I recommend to install an air pump in to your aquarium as this will insure that the water is well oxygenated. You can pickup an air pump online from amazon.

Otocinclus Tank Setup

There are certain things we need to consider when we are selecting a tank. They:

  • prefer a lot of space as they are active and love to swim around
  • like to have suitable decorations, plants, and substrates in their tank.
  • need their tank to be always neat and clean.
  • require low nitrite and ammonia level.
  • keep the growth of algae constant and stable.

1. Filtration

The cleaner your tank water is the more chance your fish have of thriving and living a happier and healthier life. I have always used a fluval aquarium filter which I highly recommend, Check them out here

2. Heater

It is recommended to use an aquarium heater to keep the water temperature at the recommended setting. If you are after a heater check out the ones available on amazon

I also recommend that you monitor your aquariums water temperature by using an aquarium digital thermometer. Check out these ones from amazon

3. Tank Decorations

It is very necessary to add decorations to your Otocinclus catfish’s tank. When adding the decoration, you should liken the tank to its natural habitat to give the fish the feeling of home. Suitable decorations include; plants, fine-grained substrates, rocks, and structures like caves for sheltering the fish when stressed.

endlers tank setup

Otocinclus Tank Size

Otocinclus catfish do not require large size tanks because of their small size. They love to swim fast in the tank and are very active, so you should provide them a tank that can allow them to exhibit their swimming abilities.

They do not require tall tanks but broad ones because they are bottom dwellers.

  • 4 to 6 Otocinclus catfish can fit perfectly in a 10-gallon tank.

You can also provide a much larger tank as they will thrive in large tanks also. If you want to add more fishes to the tank, you will need to increase its size

How many Otocinclus catfish to keep in a 5 gallon tank?

A 5-gallon tank can accommodate 2 to 3 Otocinclus catfish successfully. It is suitable for fewer numbers and not ideal for larger numbers of fish.

If you are looking to purchase a fish aquarium I recommend you check out the aquariums on amazon.

Otocinclus catfish diet

Otocinclus Diet

1. How often do Otocinclus catfish need to be fed?

Otocinclus catfish eat constantly and how often you feed them depends on how fast they are growing. However, as they grow fast, they tend to eat more often, which you might need to feed them 2 to 3 times a day. Their response when you feed them also tells if they want to eat or not.

2. What should I feed my Otocinclus catfish? 

Otocinclus catfish feed mainly on soft algae build-up that grows on the surface of hard materials in their tank. They also feed on a few plants or vegetables like the Zucchini. Their diet can consist of zucchini slices and algae wafers.

3. How long can Otocinclus catfish live without food?

Otocinclus catfish can live for about 5 to 7 days without food. But it is safer when you have algae on the surface of materials in the tank. They can feed on this for a while and ensure a longer time for starvation while you are away.

Are Otocinclus Easy to Breed?

No. Although otocinclus don’t normally pair easily, a high-protein diet can persuade your fish to mate.

When breeding your Otocinclus, daphnia, algae wafers, and brine shrimp are all fantastic feeding options.

To contain all the impending fry, your mating tank must be at least 20 gallons in volume.

How to tell if Otocinclus catfish is pregnant

There are not many ways to know if an Otocinclus catfish is pregnant. The most visible way is the swollen stomach of the female. The stomach becomes gradually big as the eggs mature.

You will also notice that the fish will respond slowly to interactions as it will prefer to stay in cool areas undisturbed.

YouTube video

Common Otocinclus Diseases

The last thing I want to go through is the common diseases these fish could suffer from.

1. Cotton Mold

The cotton mold is a parasitic infection caused by Saprolegnia, a fungus. When affected, the fish starts to grow fluffy cotton-like material on its:

  • body
  • fins
  • gills

You can treat this infection using:

  • formalin
  • copper sulfate
  • malachite green
  • hydrogen peroxide
  • sodium chloride

However, prevention is the best bet.

2. White Spot Disease

This disease is the most common disease that affects aquatic creatures as a whole. White spots, which result from protozoan activities, start to appear on the body of the fish.

Common symptoms are:

  • difficulty breathing
  • loss of appetite

However, you can treat this disease using malachite green, formalin, or aquarium salt.

3. Gold Dust Disease

The parasite that causes the gold dust disease attaches itself to the skin or gills of the fish, and you start to observe the dusty yellow spots on its skin.

Common symptoms include:

  • rapid movements of gills
  • lethargy
  • labored breathing
  • loss of appetite

However, you can take care of the disease using copper sulfate, malachite green, methylene blue, acriflavine, etc.

9 Frequently Asked Questions:

Below are the frequently asked questions about this fish:

1. What is the best substrate for Otocinclus catfish?

Otocinclus catfish require fine substrate in their tank to help them thrive. They will do with varieties of the substrate, but the best to get is a finely-grained sand substrate.

2. How many Otocinclus catfish should be kept together?

You can keep several Otocinclus catfish together in the same tank, but you have to be careful you don’t overcrowd them. You can keep a school of 5 to 6 Otocinclus catfish together.

3. Can you keep one Otocinclus catfish?

Yes, you can keep one Otocinclus catfish in a tank. But it is best if there are other catfish it can interact within the tank.

4. Will Otocinclus catfish eat moss balls?

Otocinclus catfish will eat moss balls because moss balls are from algae, and these fish feed on algae.

5. Do Otocinclus catfish produce lots of waste?

Fish that feed on algae produce much waste, but the Otocinclus catfish does not produce lots of waste compared to other algae-eating fish.

6. Can Otocinclus catfish live with goldfish?

Otocinclus catfish and goldfish have different water requirements, which make it impossible for them to live together.

7. Do Otocinclus catfish eat plants?

Yes, Otocinclus catfish eat plants, but they mostly feed on algae. They can also be very picky when it comes to plant eating.

8. Will Otocinclus catfish eat baby shrimp?

Otocinclus catfish do not eat shrimps and will not eat baby shrimps. Shrimps are suitable tankmates of Otocinclus catfish.

9. Are Oto catfish nocturnal?

Many catfish are nocturnal, but Otocinclus catfish are not nocturnal. They are active in the day. Also, they only display nocturnal behaviours when they are in a community tank where they have to hide from other fish.


Thanks for visiting HelpUsFish.com for this article on my favorite little Otos. Check out our home page and search bar with hundreds of aquatic or marine life articles to choose from. Bye for now!


Hello, I'm Jason. I'm the guy behind HelpUsFish.com. I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.