New 🐟 Mercury Safety Guide & Omega-3 Rankings Updated for 2026. View Omega-3 Rankings →

🌊 Marine Least Concern 🐠 Aquarium 🌡️ Subtropical

Flatface seahorse

Hippocampus planifrons Peters, 1877
Max Length
-
Max Weight
-
Lifespan
-
Trophic Level
3.4
Depth
0–20 m
Climate
Subtropical
Resilience
High
Vulnerability
12.00/100
Typical Length
-
Depth Zone
demersal

📖 Overview

Adults inhabit shallow algae or weedy reef areas from the intertidal to about 20 m depth . Maximum length is based on a straight-line length measurement from upper surface (ignoring spines) of first trunk ring, to tip of tail . Ovoviviparous . The male carries the eggs in a brood pouch which is found under the tail .

Scientific Name
Hippocampus planifrons
Authority
Peters, 1877
Habitat
Marine
Climate
Subtropical
Body Shape
Other
IUCN Status
LC
Depth Range
0–20 m
Trophic Level
3.4
Resilience
High
Vulnerability
12.00/100
Migration
Non-migratory
Salinity
30–40 ppt

🐟 Physical Description

Dorsal spines (total): 0; Dorsal soft rays (total): 22 - 23; Anal spines: 0; Anal soft rays: 4 - 5. Anal fin rays divided at base; tail rings 36-38; subdorsal spines 4/0,0,1,1 or 5/0,0,1,1,1; nose ridge slightly raised, without a spine; spine above eyes moderately large, angled back and laterally outward; lateral head spine moderately large and recurved; coronet slightly raised, apex with 5 blunt diverging spines; upper shoulder-ring spine of small to moderate size, situated beside gill openings; central shoulder-ring spine of moderate size and directed laterally outward; superior trunk and tail ridges with broad thorn-like blunt spines, enlarged on some rings, at regular intervals; superior tail ridge with tubercle-like spines of moderate size, angled backward; trunk ridges followed by connecting tail ridges with spines and tubercles becoming gradually smaller posteriorly; lateral line with distinct pores, on trunk rings just above lateral ridge, continuing onto tail to 18th-23rd tail ring, each pore between raised papillae .: other.

🌀 Behaviour

Behavioural data for Flatface seahorse is currently being reviewed.

🦐 Diet

aquatic invertebrates
small fish
algae
detritus

🥚 Reproduction

🐣 Oviparous 📦 Batch Spawner
Spawning Season
spring-summer
Spawn Location
Pelagic
Fertilization
External

Male carries the eggs in a brood pouch .

🌍 Habitat & Distribution

Marine; demersal; non-migratory; depth range 0 - 20 m . Subtropical; 18°S - 26°S Indian Ocean: Western Australia.

🌿 Ecology

Zone Preferences
🌊 Marine ⬇️ Benthic
Migration
Non-migratory
Trophic Level
3.4±0.4

📐 Morphometrics

Length–Weight Relationship: W = 0.00447 × L3 (TL)
Dorsal Rays
23
Anal Rays
5

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Least Concern
Assessment Date
2016

📊 Population Risk & Fisheries

Population Resilience
High
Minimum doubling time
Fishing Vulnerability
12.00/100
Low vulnerability
Trophic Level
3.4
Predator
Body Shape
Other
Climate Zone
Subtropical
Described By
Peters, 1877

👥 Community & Contribute

Aquareap Community Observations
0 Observations logged on Aquareap

No observations yet - be the first to log one!

View all observations for Flatface seahorse ↗
Suggest an Edit

Spotted incorrect or outdated data? Submit a correction and our editorial team will review it. Approved edits go live within 48 hours.

Link to a scientific paper, FishBase, or other authoritative source
Report an Issue

Found a factual error, broken data, or inappropriate content? Let us know and we will investigate promptly.