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

🌊 Marine Least Concern 🌡️ Tropical

New Zealand pygmy sleeper

Thalasseleotris iota Hoese & Roberts, 2005
Max Length
3.3 cm
Max Weight
-
Lifespan
-
Trophic Level
3.1
Depth
2–34 m
Climate
Tropical
Resilience
-
Vulnerability
10.00/100
Typical Length
-
Depth Zone
reef

📖 Overview

Observed to be solitary and possibly, a territorial species. Inhabits broken rocky reefs with holes, crevices, and small caves; perches on rocky ledges partly overlain by silty sand or shell debris. Reported to be often collected underwater sharing caves with much larger black gobies Gobiopsis atrata. Its small size, cryptic habit, semi-transparency, and camouflage coloration make this fish very difficult to locate underwater; though readily collected with rotenone ichthyocide while scuba diving. The habitat of this species in New Zealand is very similar to that of T. adela in Australia, which is restricted to rocky reefs, often in silty turbid waters, at 1-24 m depth. May be collected using slurp gun or hand collected following controlled use of rotenone ichthyocide .

Scientific Name
Thalasseleotris iota
Authority
Hoese & Roberts, 2005
Habitat
Marine
Climate
Tropical
IUCN Status
LC
Max Length
3.3 cm
Depth Range
2–34 m
Trophic Level
3.1
Vulnerability
10.00/100
Salinity
30–40 ppt

🐟 Physical Description

Dorsal spines (total): 7 - 8; Dorsal soft rays (total): 8 - 10; Anal spines: 1; Anal soft rays: 7 - 9. Diagnosis: This species differs from T. adela Hoese & Larson, 1987, in having a narrower gill opening, extending forward to below posterior margin of eye or slightly behind eye (vs. under middle of eye); less extensively scaled body, with naked area reaching to below second dorsal origin or beyond (vs. near end of first dorsal fin); higher transverse scale count (usually 7 - 8 vs. 6 - 7); modally lower vertebral count (10+16 vs. 10+17); anterior nasal tube distinctly longer than posterior nasal tube (vs. subequal); two anal pterygiophores before first haemal spine (vs. 1); uppermost scale and lowermost scale on base of caudal fin with enlarged peripheral cteni (vs. no enlarged peripheral cteni). There are several color differences, including: lacking a black spot posteriorly on the first dorsal fin; usually 5 - 6 small black more or less rounded spots on the ventral midline of the caudal peduncle (vs. usually 4 horizontally elongate black spots); a broad black or dark brown area on basal third of pectoral fin (vs. no distinct black area or a small black spot dorsally on proximal upper 2 - 3 rays); dorsal, anal, and caudal fins with thin wavy grey lines (vs. uniformly pigmented); and no dark dorsomedian line on band before first dorsal fin .

🌀 Behaviour

Behavioural data for New Zealand pygmy sleeper is currently being reviewed.

🦐 Diet

aquatic invertebrates
small fish
algae
detritus

🥚 Reproduction

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

🌍 Habitat & Distribution

Marine; reef-associated; depth range 2 - 34 m . Tropical Southwest Pacific: New Zealand.

🌿 Ecology

Zone Preferences
🌊 Marine 🪸 Reef Associated
Trophic Level
3.1±0.4
🧍 Solitary

📐 Morphometrics

Length–Weight Relationship: W = 0.00389 × L3.12 (TL)
Max TL
3.3cm
Dorsal Spines
8
Dorsal Rays
9
Anal Spines
1
Anal Rays
8

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Least Concern
Assessment Date
2024

📊 Population Risk & Fisheries

Fishing Vulnerability
10.00/100
Low vulnerability
Trophic Level
3.1
Predator
Climate Zone
Tropical
Described By
Hoese & Roberts, 2005

👥 Community & Contribute

Aquareap Community Observations
0 Observations logged on Aquareap

No observations yet - be the first to log one!

View all observations for New Zealand pygmy sleeper ↗
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.