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Otocinclus catfish, often called “Otos,” are known as some of the best algae-eating fish for freshwater aquariums. Native to South American rivers, these small catfish are prized for grazing algae off glass, plants, and decorations—making them an essential part of any tank’s cleanup crew. They have distinctive black markings and a mottled appearance, easily standing out among nano fish.
Otocinclus have a reputation for being sensitive, mainly due to their need for consistent food and gut bacteria. They are constant grazers and need a steady food supply to maintain digestive health. At Flip Aquatics, we supplement their diet with Bacter AE and ShrimpFit and quarantine new arrivals for at least two weeks. When properly cared for, Otocinclus are beginner-friendly and easy to keep.
A balanced diet is key for Otocinclus. We feed ours the following:
This variety ensures proper nutrition, especially when natural algae is limited.
All Otocinclus Catfish orders are backed by our 100% Live Arrival Guarantee. We use proven shipping methods to ensure your fish arrive healthy. If any issues arise, simply provide photos and we’ll refund or replace your fish. Orders may take up to a week to ship based on availability.
We recommend a minimum tank size of 5 gallons, but 10+ gallons is ideal for keeping Otocinclus in groups of 3 or more. Stable water conditions, especially during the first week, are crucial. They do best in mature aquariums with established algae and biofilm, along with plenty of cover from plants, driftwood, and rocks.
They do best in groups of 3 or more to reduce stress and promote natural behavior. Otos are peaceful and enjoy being part of a small school.
Yes, they are excellent at eating soft green algae and diatoms. They graze constantly and are especially known for cleaning glass and hard surfaces.
Yes, Otocinclus are peaceful and safe with shrimp, snails, and other non-aggressive fish. We’ve never seen them harm shrimp—even baby shrimp.
My Ottos arrived healthy, quickly, and packaged very well! They settled right in and have been thriving.
I received high quality fish. Would buy fish from this company again
Got them 2 weeks ago they are happy and healthy
I am so glad I went ahead and got a few of these Otos... They're so precious, and I adore them. Looking forward to the day I can buy a few more.
It’s very difficult in this hobby to find healthy ottos that arrive with full bellies and ready to eat. These guys definitely delivered! I will be buying all of my fish from them in the future!! I bought ten and they are all still active and thriving week one. Today is the week anniversary of their gotcha day. 🥰🥰
The pictures show the difference of the tank from the time I got them until about four days later lol.
My first experience with Otos and they arrived healthy and happy! Followed the instructions for acclimation and they are doing well in the tank!
Our Otos are enjoying their tanks. Placed 3 in each tank. They have feated on biofilm on Driftwood and eating algae wafers. Would order again.
Ordered Otocinclus, orphan fish and Cherry Shrimp to arrive near Christmas. I have always driven the 45 minutes to pick up from Flip and never had an issue. Due to Xmas Holiday the shipment that was to be at my house by 1:30 did not arrive until after 5:30. 2 Otocinclus arrived dead, but the Flip Folks had included an extras so I got what I needed, and the survivors look great and are doing a great job in my tank full of Anubis’s. Cherry shrimp and Orphan fish all came through the shipping great. All critters were acclimated per Flip Aquatics excellent instructions in 3 different aquaria and look great.
Happy New Year and Thank You to all at Flip Aquatics!!! A Flip Panda Gara just photobombed my OtoPhoto!
Just beyond impressed with the health of the 3 Otocinclus I ordered from Flip. They are going strong and took to the Repashy Soilent Green really quickly. Looking forward to keeping these fish for a long time!
All are doing great. Fat little bellies. They also love their zucchini.
Recieved 4 oto cats, and almost couldn't cut the bag because they kept flinging thenselves up the bag. Once they were acclimated they integrated perfectly into my community tank. I love their big pearly bellies
He came healthy but shy. He has lots of food to eat and getting a bit chunky 🤣
Fast Shipping. Very well packaged. I’m impress. I ordered 6 Otocynclus and they added an extra one for me. Love all my catfish. I highly recommend this seller. A+++
Ordered two to go in a tank that is meant to be primarily a shrimp tank. They looked great when I arrived and as I acclimated them to the tank, but once I got them into the tank they colored up and are even more impressive to look at that bottle top in the picture is from a different tank I threw together to house whisker shrimp that were sold as ghost shrimp. It was covered in green algae and I was hoping to seed the tank walls with it The order was packaged extremely well.
4/4 survived the trip! Thanks!
Ordered 5 otos and they arrived with a friend! A month later, I’m happy to say that all six are living their best lives with my shrimp and snails. I’ve been curious about otos for years, but was afraid they might be too fragile to deal with. These fish were in very good shape when they arrived, not skinny and scraggly-looking. I followed the acclimation instructions and kept the lights dim for for a day or so. They were out and about immediately.
Since the website mentioned the type of kelp wafers they were eating, I bought those, too. My shrimp go nuts for them, and the otos are on them after they get soft and start to break up. I was relieved to see them accept other foods besides algae. Canned green beans are happily enjoyed by all, as well.
These guys are so fun to watch, and I think their smart body stripes and checkerboard tails are very pretty. They don’t bother my shrimpies, except for lounging in their food dish. Hahaha
I ordered first time with FlipAquatics and I am super happy with my purchase! All my 4 Otos arrived actively and even my 20 assorted Neo shrimps. Would love to purchase again!
Received my oto's on Thursday super healthy and packaging was amazing. It's now Monday and my oto's are breeding!
My fish and shrimp arrived happy, healthy and the shipping is excellent. I'd order again.
I love these little guys. I waited 3 weeks or so to say anything because I’ve heard Oto cats can be sensitive during the acclimation period, but these fish seemed in great health when I received them and they are still doing great. They are extremely efficient algae eaters. My tank went from green to clear in 3 days. They are a cute and helpful addition to the tank.
The guys at flip are amazing! The package of otos and rcs arrived so quick and were packaged with a heating pad and an extra oto/rcs! All super healthy and making the tank look great:)
Ordered 6, got 7. Paid for the one day shipping and all 7 came in alive and were very lively in the bag!
Great purchase, thanks Flip Aquatics!
