Golden dwarf sucker

Otocinclus macrospilus

Also known as golden oto

FreshwaterFish

Golden dwarf sucker (Otocinclus macrospilus) — Rainer Schmitt, 2004 · CC BY-SA 3.0

Care at a glance

Temperature: 70–79°F (21–26°C)
pH: 6.0–7.5
Adult size: 1.4 in (3.5 cm)
Minimum tank: 11 gal (40 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Bottom
Difficulty: Medium
Breeding: No record
Rarity: Common
Origin: Peru, Colombia, Ecuador
Family: Loricariidae

Overview

These are social grazers, so keep them in a group of at least six. They spend their time on the glass, rocks, and leaves, working over algae and biofilm at the bottom and mid levels. They are completely peaceful. Keep the water in the low to mid 20s C with pH from 6 to 7.5. Algae alone will not feed them once it runs low, so offer blanched vegetables like zucchini and add catfish or algae wafers.

In the wild

This little sucker comes from clear, flowing streams in the upper Amazon across Peru, Colombia, and Ecuador. The water is soft and slightly acidic, with plants and surfaces covered in algae and biofilm. A mature, planted tank with a bit of current suits them. They do best added to an established setup, not a brand new one.

Good to know

Otocinclus macrospilus is a small armored catfish in the family Loricariidae. Adults stay tiny, around 3.5 cm. They have a sucker mouth for clinging to surfaces and grazing. Breeding in aquariums is rarely recorded, and most fish are still wild collected.

Did you know

A common mistake is starving them in a too-clean tank. Once the natural algae is gone, they need supplemental feeding or they slowly thin out, which is a big part of why they are rated harder to keep than their easygoing nature suggests.