Otocinclus (Oto)

Macrotocinclus affinis

The Otocinclus (*Macrotocinclus affinis*), known to everyone as 'Oto', is unanimously considered the best algae cleaner for small planted aquariums (Aquascaping). This tiny loricariid (just 4-5 cm / 1.5-2 inches) sports a silvery-golden tapering body, crossed by a marked black lateral band, and is equipped with a sucker mouth perfectly adapted to scrape the algal microfilm from the most delicate leaves without damaging them. Despite its immense commercial popularity, it is a fish shrouded in a tragic paradox: although sold to beginners as an easy 'scavenger fish', it is actually a very fragile species, with terrifying mortality rates in the first month of captivity due to the ruthless wild capture process and systematic malnutrition.

Family: Loricariidae
Origin: Sud America (Fiumi costieri sud-orientali del Brasile intorno a Rio de Janeiro)
Tank use: Used in 0 tanks

Temperature

21 °C - 26 °C

6 - 7.5

Water type

Freshwater

Tank level

Tutte le zone. Spesso incollati alle grandi foglie (Anubias), ai vetri o sui rami di manzanita.

Adult size

4 cm

Description

Forbidden to Those with Big Mouths:

These fish are the equivalent of a lethal spiky candy. They possess sharp and rigid spines on their lateral and dorsal fins. If you insert them with an adult Angelfish or a slightly larger fish, it will try to swallow them in one gulp; the Otocinclus will snap its spines open, becoming irreversibly lodged in the predator's throat, leading both to a slow death by asphyxiation stuck together.

Care and observations

The First Month Massacre (Forbidden to Beginners):

The Otocinclus is not born in an aquarium. They are all stunned with poisons or caught exhausted in the rivers of South America, shipped in overcrowded bags for weeks, without food. When they arrive in your aquarium they are terrified, with dead digesting bacteria and blocked intestines (look to see if the belly is hollowed out). In 50% of cases they will die in the first week due to accumulated shock, no matter how beautiful your water is. Buy them only if you are prepared to see many die at the beginning.

Not in New Aquariums (Death by Starvation):

The most common and deadly mistake is buying an aquarium, waiting a month, and buying an Otocinclus "to keep it clean". The Otocinclus eats continuously only a micro-film of invisible bacteria and green algae (biofilm). In a new or too clean aquarium, this film does not exist. The fish will starve to death desperately smacking its mouth on clean glass. The aquarium must be at least 6 months old, full of real logs and leaves.

Loneliness Kills (Minimum 6):

Being the tiniest and most defenseless prey in the river, in nature they live in swarms of thousands of individuals. If you buy only one as a "cleaning tool", the fish will live paralyzed by terror constantly hiding until it dies. Strictly purchase a small school of 6 specimens to give them courage.

Fish profile

Temperament: Timidezza e pacifismo estremi. Totalmente inermi. Spesso ignorano anche i propri simili durante il foraggiamento, pur necessitando della loro presenza per sentirsi sicuri.
Diet: Erbivoro / Grazers di Aufwuchs. La dieta è la causa del 90% delle morti. MANGIANO SOLO ALGHE E BIOFILM. Raramente accettano wafer di spirulina. Assicurarsi che abbiano sempre a disposizione pietre coperte di alghe o verdure fresche ancorate al fondo. Se l'acquario è "troppo pulito", moriranno di fame.
Tank level: Tutte le zone. Spesso incollati alle grandi foglie (Anubias), ai vetri o sui rami di manzanita.
Minimum group: 6
Adult size: 4 cm
Minimum tank: 60 L
GH: 2 dGH - 15 dGH
KH: n/a
TDS: n/a
Conductivity: n/a
Sex ratio: Branco stretto obbligatorio (minimo 6 esemplari). Essendo piccolissimi e in fondo alla catena alimentare, un esemplare solitario si nasconderà permanentemente nello stress fino a deperire. Le femmine sono visibilmente più larghe, alte e arrotondate rispetto ai maschi molto smilzi.
Feeding frequency: Cibo vegetale fresco sempre a disposizione (cambiato ogni 24h per non inquinare).
Bioload: Bassissimo
Flow: Corrente da Moderata a Forte. Provengono da torrenti altamente ossigenati.
Reproduction: Difficile ma possibile in acquari molto maturi e stabili. A differenza della maggior parte dei loricaridi, non depongono in caverne: disperdono e incollano singole uova trasparenti sotto le foglie delle piante o sui vetri, spesso in risposta a massicci cambi con acqua più fredda.
Compatibility: Mantenimento perfetto solo con pesci altrettanto minuscoli, gentili e che non competono per le alghe (Boraras, Corydoras nani, Caridina/Neocaridina). ASSOLUTAMENTE DA EVITARE Betta aggressivi, Ciclidi nani, Ancistrus o Pleco (che mangerebbero tutte le loro alghe condannandoli alla fame) o pesci grossi che li ingoierebbero interi bloccandosi la gola.

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.