Peacock grouper
Cephalopholis argus
Also known as Blue-spotted grouper, Argus grouper, Peacock hind, Blue dot grouper
SaltwaterFish
Care at a glance
- Temperature
- 75–81°F
- 24–27°C
- pH
- 8.0–8.4
- Adult size
- 23.6 in
- 60 cm
- Minimum tank
- 251 gal
- 950 L
- Temperament
- Aggressive
- Social behavior
- Solitary
- Own kind
- One per tank
- Tankmates
- With caution
- Swim level
- Bottom
- Difficulty
- Difficult
- Breeding
- No record
- Rarity
- Common
- Reef safe
- Reef safe with caution
- Family
- Serranidae
- Origin
- Native to the Indo-Pacific and introduced to Hawaii, living on coral reefs and lagoon slopes where it hunts small fish.
Overview
Plan for an adult near 60 cm and a tank of at least 950 litres, more is far better, with heavy filtration for the messy carnivore load. Keep it at 24 to 27 C and pH 8.0 to 8.4 in a fish-only system with big caves. It will swallow any fish or shrimp that fits in its wide mouth, so only pair it with equally large, tough tankmates. Feed meaty seafood a few times a week and expect fast growth.
In the wild
The peacock grouper is a dark brown to olive hind speckled with electric blue spots and pale vertical bars that flare when it is excited. It is a powerful ambush predator that reaches around 60 cm and grows into a genuinely large, greedy fish. Cute palm-sized juveniles are sold cheaply and quickly outgrow most tanks.
Good to know
Cephalopholis argus is a protogynous hermaphrodite that defends harems of females on the reef. It was deliberately introduced to Hawaiian waters in the 1950s as a food fish and is now considered an invasive predator there. Adults can carry ciguatera toxin from their wild diet.
Did you know
In Hawaii the peacock grouper, known locally as roi, is targeted by spearfishing tournaments because it competes with native reef fish that people prefer to eat.
Common questions
What size tank does a Peacock grouper need?
A Peacock grouper needs at least 251 gal (950 L). It spends most of its time in the bottom.
What temperature and pH does a Peacock grouper need?
A Peacock grouper is comfortable at 75–81°F (24–27°C) with a pH of 8.0–8.4.
How big does a Peacock grouper get?
An adult Peacock grouper reaches about 23.6 in (60 cm).
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