Scissortail Dartfish

Ptereleotris evides

Also known as Scissortail Goby, Blackfin Dartfish, Arrow Dartfish

SaltwaterFish

Scissortail Dartfish (Ptereleotris evides) — Poco a poco · CC BY-SA 4.0

Care at a glance

Temperature: 72–79°F (22–26°C)
pH: 8.1–8.4
Adult size: 5.5 in (14 cm)
Minimum tank: 29 gal (110 L)
Temperament: Peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Easy
Breeding: Hard
Rarity: Common
Reef safe: Reef safe
Origin: Indo-Pacific, from the Red Sea and East Africa to the Line and Society Islands, north to the Ryukyu Islands and south to Lord Howe Island
Family: Ptereleotridae

Overview

Scissortail dartfish are peaceful and fully reef safe, ignoring corals, clams, and other invertebrates entirely. They are social and do best in a group of three or more, hovering together above the sand in a loose formation and behaving far more confidently than a single fish kept alone. They get along with other peaceful tankmates but should not be paired with boisterous fish that will bully them away from the open water they like to patrol. Feed a variety of small meaty foods, mysis, brine shrimp, and finely chopped seafood, a couple of times a day since they are constant, energetic feeders. Their biggest risk in captivity is jumping, so a secure lid is not optional.

In the wild

Ranges across the Indo-Pacific from the Red Sea and East Africa to the Line and Society Islands, on outer reef slopes and in lagoons at depths of about 2 to 15 meters. It hovers just above a shared burrow system in sand or rubble and drops down out of sight the instant it feels threatened. The aquarium should have a few inches of sand for burrowing, loose rubble or rockwork nearby, open water for hovering, and a tight fitting lid, since this is a strong jumper when startled.

Good to know

A dartfish in the family Ptereleotridae, also called the blackfin dartfish, reaching about 14 cm, with a two tone body, pale blue-grey up front shading to black across the rear half and tail. The tall, forked tail gives rise to the scissortail name, since the two lobes open and close like blades as it swims. Unlike true gobies it has no fused pelvic sucker and swims freely in open water, retreating to a shared burrow rather than resting flat on the bottom.

Did you know

When startled, a scissortail dartfish does not bolt for the nearest rock like most fish. It drops straight down into its burrow in the sand, vanishing from view in a fraction of a second before cautiously easing back up minutes later.