Knaack's cory
Hoplisoma knaacki
Also known as Corydoras knaacki
FreshwaterFish
Care at a glance
- Temperature
- 73–81°F
- 23–27°C
- pH
- 5.8–7.2
- Adult size
- 1.8 in
- 4.5 cm
- Minimum tank
- 16 gal
- 60 L
- Temperament
- Peaceful
- Social behavior
- Shoaling
- Swim level
- Bottom
- Difficulty
- Medium
- Breeding
- Medium
- Rarity
- Rare
- Family
- Callichthyidae
- Origin
- Rio Madre de Dios basin, southeastern Peru
Overview
Knaack's cory is a peaceful Peruvian cory for a sand-bottomed community tank. It is a good fit for a keeper past the beginner stage.
Did you know
Knaack's cory often swims beside Fuller's cory in the same Peruvian rivers. Knaacki is named for Joachim Knaack, a describer of Bolivian cories, and fulleri for the man who codes the unnamed ones.
Caring for the Knaack's cory
Knaack's cories do well as a shoal of six or more, in a tank of at least 16 gal (60 L). Give them fine sand, wood and leaves, with clean, flowing water.
Keep the water at 73 to 81°F (23 to 27°C) and a pH of 5.8 to 7.2. They eat prepared sinking foods right away.
They are peaceful and make good companions for pencilfish and small Peruvian tetras. Knaack's cories breed along standard cory lines, with cool water changes as the trigger. Keepers can draw on several hobby reports, and the fish are moderately hard to breed.
Good to know
Knaack's cory was described in 2016 by Tencatt and Evers. The 2024 revision lists it as Hoplisoma knaacki, in the family Callichthyidae. It is one of the round-snouted, spotted cories of the Madre de Dios that hobby lists once lumped under catch-all names.
In the wild
Knaack's cory lives in sandy lowland streams of the Rio Madre de Dios basin, in southeastern Peru.
Weekly picks
Tank mates
The Knaack's 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.
White spotted rabbit snail
Tylomelania towutica
Freshwater4.3 in (11 cm) · 16 gal (60 L)75–84°F (24–29°C)
Harrison's pencilfish
Nannostomus harrisoni
Freshwater2.2 in (5.5 cm) · 16 gal (60 L)73–82°F (23–28°C)
Spotted splash tetra
Copella nattereri
Freshwater2 in (5 cm) · 16 gal (60 L)75–82°F (24–28°C)
Kuhli loach
Pangio kuhlii
Freshwater3.9 in (10 cm) · 17 gal (65 L)72–82°F (22–28°C)
Gold rabbit snail
Tylomelania gemmifera
Freshwater2.8 in (7 cm) · 16 gal (60 L)75–82°F (24–28°C)
Brittan's rasbora
Kottelatia brittani
Freshwater2.4 in (6 cm) · 16 gal (60 L)68–79°F (20–26°C)
Common questions
What size tank does a Knaack's cory need?
A Knaack's cory needs at least 16 gal (60 L). It spends most of its time in the bottom.
What temperature and pH does a Knaack's cory need?
A Knaack's cory is comfortable at 73–81°F (23–27°C) with a pH of 5.8–7.2.
What does a Knaack's cory eat?
A Knaack's cory eats prepared sinking foods right away.
How big does a Knaack's cory get?
An adult Knaack's cory reaches about 1.8 in (4.5 cm).
Does a Knaack's cory need a group?
Yes. A Knaack's cory is a shoaling species and should be kept in a group, not singly.
How does a Knaack's cory breed?
Knaack's cories breed along standard cory lines, and cool water changes set them off. Several hobby reports exist for keepers to draw on.
Related species
1.8 in (4.5 cm)15 gal (55 L)75–82°F (24–28°C)Apiaka cory
Hoplisoma apiaka
1.8 in (4.5 cm) · 15 gal (55 L)
1.8 in (4.5 cm)16 gal (60 L)73–79°F (23–26°C)Blackfin cory
Hoplisoma leucomelas
1.8 in (4.5 cm) · 16 gal (60 L)
1.8 in (4.5 cm)15 gal (55 L)75–82°F (24–28°C)Kane's cory
Hoplisoma kanei
1.8 in (4.5 cm) · 15 gal (55 L)
2 in (5 cm)15 gal (55 L)70–79°F (21–26°C)Blackstripe cory
Hoplisoma bondi
2 in (5 cm) · 15 gal (55 L)
2 in (5 cm)16 gal (60 L)70–75°F (21–24°C)Dirty bandit cory
Hoplisoma loxozonum
2 in (5 cm) · 16 gal (60 L)
2 in (5 cm)20 gal (75 L)72–79°F (22–26°C)Duplicate cory
Hoplisoma duplicareum
2 in (5 cm) · 20 gal (75 L)