Gregory Yellowtail Damselfish

Gregory Yellowtail Damselfish (Stegastes sp.) is a semi-aggressive species that is reef-safe with caution, admired for its vivid blue-to-purple body contrasted with a bright yellow tail and fins, hardy nature, and small size that makes it a durable beginner fish.

Males typically defend territories aggressively, especially around spawning sites, and display slightly bolder coloration, while females/juveniles are less territorial and somewhat more subdued in behavior but look very similar in color.

They reach about 3 inches (7–8 cm) and should be housed in aquariums of at least 30 gallons (larger if kept with other semi-aggressive species). Provide ample live rock for hiding spots and territories, with some open swimming space, stable water parameters (salinity ~1.020–1.025, temp ~72–79°F, pH ~8.1–8.4), and a secure lid since many species are prone to jumping.

Diet should consist of a varied mix of mysis shrimp, enriched brine shrimp, copepods, high-quality marine pellets/flakes, and some algae-based foods. With proper care, this fish makes a hardy, colorful, and active addition to the aquarium, though best kept with equally assertive tank mates.

International Aquatics Quarantine & Guarantee: All fish are checked by marine vets, given a formalin bath, and held for 14 days in copper-treated systems. We feed Selcon-soaked food with Kanaplex and Metroplex during quarantine. Unless marked, all livestock comes with our 15-Day Guarantee. You will receive a video of your fish eating before shipment. On request, we also send photos/videos after arrival at IA. Some species are import-to-order (3-10 business days). Many common species are already cleared or near the end of QT.

Several species will be import-to-order and may take anywhere from 3-10 business days to secure. Once your fish is secured, you will be notified, and the quarantine process will then begin.