Ancestor cory
Hoplisoma noxium
Also known as Corydoras noxium, CW004
FreshwaterFish
Care at a glance
- Temperature
- 75–82°F
- 24–28°C
- pH
- 5.5–7.0
- Adult size
- 2.4 in
- 6 cm
- Minimum tank
- 16 gal
- 60 L
- Temperament
- Peaceful
- Social behavior
- Shoaling
- Swim level
- Bottom
- Difficulty
- Medium
- Breeding
- No record
- Rarity
- Rare
- Family
- Callichthyidae
- Origin
- Igarape do Buriti, Rio Tapajos basin near Jacareacanga, Para, Brazil
Overview
The ancestor cory is a peaceful, shoaling cory for the bottom of a small community tank. It needs a bit more care than a beginner fish.
Did you know
Keepers called CW004 the ancestor cory because its heavy mask and arch look like the pattern other cories seem built from. The hobby name came first, and science only caught up in 2025.
Caring for the ancestor cory
Keep ancestor cories in a group of six or more, in a tank of at least 16 gal (60 L). Give them fine sand, wood for shade and leaf litter.
Keep the water clean and oxygen rich, at 75 to 82°F (24 to 28°C) and a pH of 5.5 to 7.0. Feed sinking granules, wafers and frozen foods.
Ancestor cories are model peaceful shoalers and are safe with other community fish. There is no published breeding report. The standard cool water change method is the obvious starting point if you are lucky enough to hold a group.
Good to know
The ancestor cory was described as Hoplisoma noxium by Tencatt, Ohara, Carvalho, Grant and Britto. Related color forms carry the codes CW155, CW156 and CW167. Imports remain scarce and sought after.
In the wild
The ancestor cory comes from the Igarape do Buriti, a small forest stream in the Tapajos basin near Jacareacanga, Para, Brazil. It shoals over sand there, in warm, gently acidic water.
Weekly picks
Tank mates
The ancestor cory is a peaceful, shoaling species that keeps to the bottom. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.
Merry widow livebearer
Phallichthys amates
Freshwater2.5 in (6.4 cm) · 16 gal (60 L)72–86°F (22–30°C)
Spotted splash tetra
Copella nattereri
Freshwater2 in (5 cm) · 16 gal (60 L)75–82°F (24–28°C)
White spotted rabbit snail
Tylomelania towutica
Freshwater4.3 in (11 cm) · 16 gal (60 L)75–84°F (24–29°C)
Guapore cory
Gastrodermus guapore
Freshwater2 in (5 cm) · 16 gal (60 L)72–82°F (22–28°C)
Cardinal toothcarp
Brachyrhaphis roseni
Freshwater2.4 in (6 cm) · 16 gal (60 L)72–86°F (22–30°C)
Fanning characin
Pyrrhulina rachoviana
Freshwater2 in (5 cm) · 16 gal (60 L)68–79°F (20–26°C)
Common questions
What size tank does an ancestor cory need?
An ancestor cory needs at least 16 gal (60 L). It spends most of its time in the bottom.
What temperature and pH does an ancestor cory need?
An ancestor cory is comfortable at 75–82°F (24–28°C) with a pH of 5.5–7.0.
What does an ancestor cory eat?
An ancestor cory eats sinking granules, wafers and frozen foods.
How big does an ancestor cory get?
An adult ancestor cory reaches about 2.4 in (6 cm).
Does an ancestor cory need a group?
Yes. An ancestor cory is a shoaling species and should be kept in a group, not singly.
Related species
2.4 in (6 cm)20 gal (75 L)70–79°F (21–26°C)Adolfo's cory
Hoplisoma adolfoi
2.4 in (6 cm) · 20 gal (75 L)
2.4 in (6 cm)16 gal (60 L)68–77°F (20–25°C)Carla's cory
Hoplisoma carlae
2.4 in (6 cm) · 16 gal (60 L)
2.4 in (6 cm)20 gal (75 L)72–79°F (22–26°C)Concolor cory
Hoplisoma concolor
2.4 in (6 cm) · 20 gal (75 L)
2.4 in (6 cm)20 gal (75 L)72–79°F (22–26°C)Froehlich's cory
Hoplisoma froehlichi
2.4 in (6 cm) · 20 gal (75 L)
2.4 in (6 cm)20 gal (75 L)72–79°F (22–26°C)Gossei cory
Hoplisoma gossei
2.4 in (6 cm) · 20 gal (75 L)
2.4 in (6 cm)21 gal (80 L)72–79°F (22–26°C)Sands cory
Hoplisoma davidsandsi
2.4 in (6 cm) · 21 gal (80 L)