IntermediateSemi-AggressiveReef Safe with CautionIUCN: Least Concern
Longspine Squirrelfish
Holocentrus rufus
Family: Holocentridae · Squirrelfish & Soldierfish
Also known as: Longspine Soldierfish, Red Squirrelfish
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Max Size
11"
Min Tank
75 gal
Lifespan
7-10 years
Origin
Western Atlantic, Caribbean
Diet
Carnivore
Swims
Middle
Did You Know?
- Squirrelfish can produce audible sounds by vibrating their swim bladder, using these sounds for communication
- Their enormous eyes contain a reflective layer (tapetum lucidum) similar to cats, enhancing their night vision
- The venomous anal spine can cause pain similar to a bee sting in humans
About
The Longspine Squirrelfish is a striking nocturnal reef fish characterized by its vivid red coloration, enormous eyes, and prominent dorsal spines. The species gets its name from the elongated third spine of the anal fin, which is noticeably longer than the others and can inflict a painful, mildly venomous sting.
In the wild, Longspine Squirrelfish are found in reef crevices and under ledges during the day, emerging at night to feed on small crustaceans, worms, and gastropods. Their large eyes are specially adapted for low-light vision, giving them a significant advantage as nocturnal hunters.
In the aquarium, they are hardy and long-lived fish that adapt well to captive conditions. They prefer dim lighting or heavily shaded areas and are most active during evening hours. While generally peaceful toward fish too large to eat, they will consume small crustaceans and very small fish. A minimum tank of 75 gallons with plenty of caves and overhangs is recommended.
Feeding & Diet
Carnivore
A nocturnal carnivore that feeds on small crustaceans, worms, and occasionally small fish. Offer frozen mysis shrimp, krill, chopped shrimp, and marine carnivore pellets. Initially may only accept food offered at dusk or after lights-out. Feed once daily, preferably in the evening.
Compatibility
nocturnalcave-dwellercarnivorevenomous-spines
Generally peaceful with fish too large to eat but will consume small shrimp and tiny fish during nighttime hunting. Compatible with most medium to large community fish. May be shy initially and hide during the day. Keep with other hardy species that won't outcompete them for food.
Check CompatibilityBreeding
Not bred in captivity
Squirrelfish are pelagic spawners that release eggs into the water column at dusk. Captive breeding has not been achieved due to the difficulty of raising the tiny larvae.
Special Requirements
- Provide plenty of caves and overhangs for daytime hiding
- Dim lighting preferred — may be stressed by intense reef lighting
- Long venomous anal spine can cause painful stings during handling
- Best fed in the evening when naturally most active
Water Parameters
Temperature72–78°F
Specific Gravity1.02–1.025 sg
pH8.1–8.4
Alkalinity8–12 dKH
Coloration
redwhitesilver
Tags
nocturnalcave-dwellercarnivorevenomous-spines
