Harlequin filefish
Oxymonacanthus longirostris
Also known as Orange spotted filefish, Longnose filefish, Beaked leatherjacket, Harlequin leatherjacket
SaltwaterFish
Care at a glance
- Temperature
- 75–81°F
- 24–27°C
- pH
- 8.0–8.4
- Adult size
- 4.3 in
- 11 cm
- Minimum tank
- 53 gal
- 200 L
- Temperament
- Peaceful
- Social behavior
- Social
- Tankmates
- With caution
- Swim level
- Middle
- Difficulty
- Difficult
- Breeding
- Hard
- Rarity
- Rare
- Reef safe
- Not reef safe
- Family
- Monacanthidae
- Origin
- Native to the Indo-Pacific, living among branching Acropora coral thickets on which it depends for food and shelter.
Overview
This fish is only realistic for advanced reef keepers with an established tank of at least 200 litres carrying a healthy growth of live Acropora coral it can graze, at 24 to 27 C and pH 8.0 to 8.4. Without live SPS coral to eat, most starve, though some can slowly be trained onto live baby brine and enriched frozen foods. It is not reef safe with Acropora, since eating those polyps is the whole point of the fish. Keep it as a peaceful pair with gentle tankmates and no food competitors.
In the wild
The harlequin filefish is a small, delicate fish patterned in pale blue-green and covered in bright orange spots, with a long tube snout for picking at coral polyps. It hovers head-down among branching corals and blends into the coral thicket. It is one of the most beautiful reef fish and one of the most difficult to feed.
Good to know
Oxymonacanthus longirostris is an obligate corallivore that in the wild feeds almost entirely on the polyps of living Acropora coral. It even smells like the coral it eats, which helps hide it from predators. Pairs stay together and defend a patch of coral, and the loss of Acropora reefs to bleaching directly threatens the species.
Did you know
The harlequin filefish takes on the very smell of the coral it eats, chemically camouflaging itself so that predators hunting by scent cannot tell the fish from the coral it hides in.
Common questions
What size tank does a Harlequin filefish need?
A Harlequin filefish needs at least 53 gal (200 L). It spends most of its time in the middle.
What temperature and pH does a Harlequin filefish need?
A Harlequin filefish is comfortable at 75–81°F (24–27°C) with a pH of 8.0–8.4.
How big does a Harlequin filefish get?
An adult Harlequin filefish reaches about 4.3 in (11 cm).
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