Naucrates ductor
| Identification | Elongated, streamlined body with 5–7 dark blue-black vertical bars on a silver-blue background. Small finlets near the tail and a deeply forked caudal fin built for fast, open-water swimming. |
| Maximum Length | Up to 28 inches (70 cm) |
| Origin | Worldwide in tropical and subtropical open oceans |
| Minimum Tank Size | 300+ gallons — open water species |
| Reef Compatible | Not applicable — open ocean pelagic species |
Behavior
Famous for its habit of swimming alongside large sharks, rays, and other large marine animals, feeding on their scraps and parasites. A pelagic species rarely suited to home aquariums due to its open-water lifestyle and eventual large size. Juvenile specimens are occasionally collected and kept, but adults require enormous systems.
Diet & Feeding
Carnivore. Feeds on parasites, scraps from host animals, and small fish. In captivity offer fresh or frozen silversides, mysis shrimp, and carnivore preparations. Strong feeder once established.
Cautions
Not suitable for typical home aquariums. Best suited for very large professional exhibits. Juveniles may acclimate but will outgrow most systems rapidly.