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This page will give a completely detailed profile of the selected fish, from A to Z. The profiled fish will be chosen randomly by Badman, and will come from the complete genre of tropical fish. New profiles are added on a regular basis. If you would like to submit a profile for the site please contact me. Don't forget to let us know you experiences with this fish by filling out the

South America


oto cat,Otocinclus sp.

Macrotocinclus macrospilus, formallly Otocinclus macrospilus


    The perfect little catfish for the community aquarium the oto will do a fine job at keeping the algae in check. Small to large aquariums will benefit from their service as this fish bothers none and is usually left alone.

Quick stats:


    Listed tank sizes are the minimum
    Size: 1.5" (4 cm)
    Tank: 16 inches
    Strata: Bottom, middle
    PH: 5.2-7.5
    Hardness: Soft to hard. dH range: 4.0 - 20.0
    Temperature: 68 to 82°F (20-28°C)


    Order: Siluriformes
    Family: Loricariidae
    SubFamily: Hypoptopomatinae
    Genera: Otocinclus
    Species: Varies

oto cat,Otocinclus sp.


    Not in IUCN Red List

Common name:

    Oto cat, Golden otocinclus, Dwarf Sucker Mouth

Image gallery:

    Additional species photographs


    Badmans' Forum


    South America, Brazil, Amazon river basin

General Body Form:

    An elongated fish with a flat belly and a slightly curved back. The eyes are set on the sides and are visible when looked at from the bottom. The mouth faces down as would be expected from a sucker type fish. This fish has no barbels or adipose fin. The pectoral, pelvic, dorsal, and anal fins are clear and the tail fin is striped .The females are more rounded or robust.


    Not one of the most eye catching fish the otos most distinct feature is the brown stripe running down the sides. The main body color is a dull gray green color. Some species the body is more yellow and is often called the golden oto. The belly is white with a hint of yellow. The back is dark.


    The oto can be difficult to acclimate to the home aquarium, but provided the water conditions are correct and there is some green food they should be OK. The set up should be well established with a sand or gravel substrate, Densely planted with live plants or an established algae growth is essential. While they will take flake food and sinking pellets the natural greens are needed to provide proper health. If no algae is available they will eat the softer bodied plants. Provide good water circulation and filtering. Best keep in groups the actual number will vary upon tank size. Fine with most fish except the larger predatory species.


    Heavily vegetated rivers of Brazil and the Amazon watershed.


    It would have to be classified as difficult. They have been bred in captivity but it seems to be a sporadic occurrence. Similar to the armored catfish the eggs are laid on the leaves of plants or on the tank glass. No care is given once they are laid. The eggs hatch in about two days and three days later the fry are free swimming. Extremely small and delicate they must be fed newly hatched brine shrimp, crushed vegetable flake food and even boiled spinach.

    Oto fry

Your comments:


Please remember that the following comments are personal experiences and may or may not apply to your setup. Use them as guide to help better understand your fish, like us all individuals will behave differently under different circumstances.


From: Kiara
I got one of these little guys as one of the first three fish to enter my planted aquarium, and haven't viewed algae in my tank since. I've done the same for several of my other tanks and not one has died, though they look perkier in groups. They are great, though mine seem to clean the tank at night and disappear during the day. Amazing little fish!
From: Dean
Otocinclus is one of my favorite species of fish. I have two in a 10 gal.(There names are Copper & T-bone) with 4 female bettas and they are the greatest. They eat the algae in the tank much better than a pleco can.(I have a pleco in a different tank.) I highly recommend getting driftwood. Driftwood seems to attract algae and my eat off it all the time. Also you MUST have life plants and a stable temperature. There not be enough algae unless you have live plants and a temperature around 77 degrees F. Have fun with otos!
From: Shaina
Oto cats are great little fish, though they often die in the first few days due to neglect during shipping. They will clean all edible (for them) algae and diatoms quickly, so be prepared to feed them veggies. A cheap way to ensure they have enough to eat is to leave a bowl with rocks submerged in tank water by the window. They will grow algae/diatoms, which you can then trade out with other tank rocks to provide a constant supply of Oto food without attempting the risky business of intentionally growing algae in your main tank.
From: Zach
I have 2 of the little guys and they are very entertaining as well as good algae eaters. They are always inching down the leaves of the mondo grass and other plant stems as well as the driftwood. They also seem to really like to eat the white growths on the CO2 diffuser. The hardest part about owning them is keeping them for the first week, as some just die for no apparent reason.
From: Taylor
I have one oto in my 10g tank and I haven't had algae since! I like the little guys so much I am going to be buying 2 more for this tank and 3 for my other tank as well! I haven't had any problems with it at all!!!
From: Burks
These little guys are my favorite cleanup crew. When I had my brown diatom outbreak someone suggested I pick up a couple Otos. Sure enough they did the trick! I now keep at least two Otos per 10g tank as I have high lights so algae grows very quickly. They are always cleaning my plants and glass. Very attractive fish too. One wouldn't think they are good looking until you have one in the tank. They can be a bit hard to find at times, and when found their health can be in question. Always drip acclimate Otos. I've had great success by drip acclimation compared to letting the bag rest on the water surface and adding water every 5-15 minutes.







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