🐠 Blue Gudgeon Dartfish (Ptereleotris heteroptera)
Marine Reef-Safe Dartfish • Pale Blue-Green Body With Black Tail Spot • Peaceful Open-Water Hoverer • Beginner-Friendly Marine Fish
 
📋 The Blue Gudgeon Dartfish (Ptereleotris heteroptera), also known as the Blacktail Goby or Blacktail Dartfish, is an elegant, elongated marine fish with a pale blue-green body that fades toward a lighter belly, topped off with a distinctive black spot right at the centre of its tail.
Native to the reefs of Fiji and the wider Indo-Pacific, this species spends its time hovering in the water column just above the substrate, darting after passing zooplankton before retreating to shelter at the first sign of danger.
Genuinely peaceful and reef safe, Blue Gudgeon Dartfish are naturally quite timid and do noticeably better in pairs or small groups introduced together, becoming visibly more confident and less secretive the larger the group. They benefit from a sandy substrate to rest near and burrow into occasionally, along with plenty of loose coral rubble and rockwork for shelter.
With gentle tank mates, a secure lid, and consistent feeding, it thrives as a Peaceful Open-Water Reef Display Fish.
 
💙⚫ Highlights
🎨 Distinctive Black Tail Spot: Bold marking against a pale blue-green body
🐟 Best Kept in Small Groups: Noticeably more confident and visible with 2–4 individuals
🌿 Genuinely Reef Safe: Won't bother fish, corals, or invertebrates
⚠️ Notorious Jumper: A tightly fitted lid is essential
🧠 Beginner Friendly: Easy care once paired with peaceful tank mates