Otocinclus macrospilus

Not open for further replies.


Retired Staff
Apr 8, 2009
Name: Otocinclus macrospilus

Common Names: Marbled Otocinclus, Oto, Otocinclus Catfish, Dwarf Suckermouth Catfish, Pygmy Suckermouth Catfish.

Location: South America: Upper Amazon Basin of Colombia, Ecuador and Peru.



An active, peaceful and completely harmless community fish, should be kept in a group of at least 5-6 specimen. The tank should be densely planted with large-leafed plants smooth rocks, bog wood, as well as a layer of crude rounded gravel as substrate, to provide hiding places as well as submerged surfaces on which algae can grow.

Sexing and Breeding:

This little catfish is often kept as a tank "de-algaefier", because of its appetite for any kind of algae. Often it eats algae faster than they can regrow, so it is of vital importance to feed these fish additionally: suitable are vegetarian food items like algae/spirulina pellets and vegetables like cucumber, zucchini, eggplant, lettuce and preboiled spinach, as well as meaty foods such as carnivore pellets, tubifex and mosquito larvae.

Water parameters:
Temp 20-28 PH 5.5-7.5
An aquarium of 24" (60cm.) in length is sufficient to provide a small shoal of these active, monkey-esque catfish ample space to thrive. A densely planted tank is preferred, so the little fish can hide and feel secure, especially when they share their tank with larger or more active fish. To accommodate a sustained algae growth, bright lights or a sunny place for the fish tank is recommended.
Optimal conditions are soft, slightly acidic water, achievable by filtering over peat or by the use of Black Water Extract. But they will do well in harder, more alkaline water as well.

Max Size: 3,5cm. (1,5").

Bred by:

Additional Comments:

Like most other Otocinclus species, the first couple of weeks in captivity are critical, and many perish during this first period. Key is proper (ie. slow) acclimatisation, a stressfree environment and a good diet (many specimen arrive malnourished). Close observation during this initial phase is recommended.
This species looks very similar to Otocinclus vittatus, but can be differentiated by looking at the pattern on the back and the dark band running along the body from head to tail: whereas Otocinclus vittatus has a uniformly colored back and a stripe that runs all the way to the tail fin, this species has a marbled coloration back and a stripe that does not runs all the way to the tail fin (see picture below).

Profile used with permission from www.piranha-info.com
Not open for further replies.