Pinnatus batfish

Platax pinnatus

Also known as Pinnate batfish, Dusky batfish, Red-finned batfish, Shaded batfish

SaltwaterFish

Pinnatus batfish (Platax pinnatus) — Liné1 · CC BY 2.5

Care at a glance

Temperature: 75–81°F (24–27°C)
pH: 8.0–8.4
Adult size: 17.7 in (45 cm)
Minimum tank: 198 gal (750 L)
Temperament: Mostly peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Difficult
Breeding: No record
Rarity: Rare
Reef safe: Not reef safe
Origin: Native to the western Pacific, with juveniles hiding in caves and on reef slopes and adults ranging over deeper reef.
Family: Ephippidae

Overview

Only experienced keepers should attempt this fish, and only in a large, mature tank of at least 750 litres with tall open water, at 24 to 27 C and pH 8.0 to 8.4. The hurdle is feeding: fresh juveniles frequently starve, so buy one only after seeing it eat and offer frequent small meals of enriched mysis, chopped seafood and grazing foods. It is not reef safe and will nip corals and eat small invertebrates. Keep it with calm tankmates, as it is easily bullied while it settles.

In the wild

The pinnatus batfish is famous for its jet-black juvenile form outlined in a brilliant orange border, one of the most beautiful young fish on the reef. As it grows it loses the orange and turns into a tall silvery-grey disc like other batfish. The juvenile stage is what people buy, but it is also where nearly all the difficulty lies.

Good to know

Platax pinnatus grows to around 45 cm and is considered the hardest batfish to keep alive because juveniles are specialised feeders that often refuse aquarium food. Research suggests young pinnatus batfish naturally eat a lot of small invertebrates and even sponge material. The dramatic black-and-orange juvenile colour fades within months as the fish matures.

Did you know

The black juvenile with its glowing orange trim is thought to mimic a toxic flatworm, borrowing the flatworm's warning colours to keep predators from biting.