Bronze Corydoras vs Otocinclus

The same axes for both animals, taken from the same care guides, so this is a like-for-like comparison rather than two articles written months apart. Neither animal is the right answer on its own. The question is which one fits the space, the budget and the routine you actually have.

Freshwater Fish
Bronze Corydoras
Osteogaster aenea
Difficulty
Beginner
Lifespan
5-10 years
Adult size
2.4-3 in
Minimum space
20 gal
Company
Must be kept in at least 6
Daily time
Low-moderate (daily feed, weekly water changes)
Running cost
Low
Habitat
Aquarium 20 gal+, at least 31.5 in long
Diet
Omnivore (bottom-feeder)
Suits you if
Beginners wanting an active bottom-dweller. Peaceful community aquariums. Keepers using sand substrate
Watch out for
Keeping fewer than 6 (they are social). Sharp gravel eroding their barbels. Assuming they survive on leftovers

Full Bronze Corydoras guide

Freshwater Fish
Otocinclus
Otocinclus vittatus
Difficulty
Intermediate
Lifespan
3-5 years
Adult size
1.2-2 in
Minimum space
24 gal
Company
Must be kept in at least 6
Daily time
Moderate (daily feed, stable mature tank)
Running cost
Low-Medium
Habitat
Aquarium 24 gal+, at least 24 in long (mature)
Diet
Herbivore (algae/biofilm grazer)
Suits you if
Mature, algae-rich planted tanks. Peaceful planted community tanks of 24 gallons or more. Keepers wanting safe algae control on plants
Watch out for
Adding to a new tank with no algae/biofilm. Buying thin, starved, hollow-bellied stock. Keeping fewer than 6 (they shoal)

Full Otocinclus guide

How to read this

Every row is filled from the same field of the same care guide for both animals, so nothing here is cherry-picked to favour one of them.

Minimum space is the figure from each species' housing guidance, converted to one unit: the smallest space that gives the animal good conditions, not a legal minimum. It is a floor, not a target.

What this does not tell you: your experience, your household, your climate, or which animal you will actually enjoy. Difficulty is our judgement, not a measurement. Read both full guides before deciding, and if the honest answer is neither, that is a good outcome too.