The orange roughy, or Hoplostethus mediterraneus, is a benthic species found mainly in deep, cold waters. Although it is not a typical target for sport fishermen in Quebec, it draws interest due to its unique appearance and fascinating biology. This fish is generally caught by deep-sea trawlers rather than by anglers. Its distribution in Quebec is limited to certain areas of the estuary and Gulf of St. Lawrence, where it lives at considerable depths, often beyond 200 meters. Its fighting ability is modest, and it does not offer the same challenge as other prized species like yellow perch or pike. However, for marine biology enthusiasts, studying it can be just as captivating.

The orange roughy has a laterally compressed body, with a relatively large head compared to its body. Its color ranges from reddish to brown, allowing it to blend into the deep and dark environments of the ocean. The scales are thick and robust, providing some protection against predators and the harsh conditions of great depths. Its fins are well developed, with notable spiny rays, particularly on the dorsal fin. The mouth is relatively wide, adapted to its diet primarily consisting of small fish and crustaceans. Males and females are similar in appearance, but females tend to be slightly larger, especially during spawning. Juveniles are paler than adults and may have spots that disappear as they age.

In Quebec, the orange roughy is mainly found in the deep waters of the estuary and Gulf of St. Lawrence. It prefers areas where the depth often exceeds 200 meters, making it difficult to access for recreational fishing. Due to its deep habitat, it is less abundant than other coastal species and is generally not targeted by sport fishermen. However, it can be accidentally caught by trawlers operating in these areas. Its global distribution also includes the Northeast Atlantic, the Mediterranean, and parts of the Pacific.

The orange roughy is a typical deep-sea species, generally living at depths ranging from 200 to 800 meters. It prefers rocky or muddy seabeds, where it can hide from predators and find its prey. The ideal temperatures for this species are between 8 and 12 °C, which corresponds to the conditions found in the depths of the estuary and Gulf of St. Lawrence. Fishermen looking to observe or catch this species will need to focus on offshore areas, well beyond coastal waters.

The life cycle of the orange roughy begins with the spawning of eggs, usually at significant depths to avoid predators. The eggs hatch into larvae that are planktonic, drifting with the currents until they reach a sufficient size to settle on the seabed. Growth is slow, and young orange roughies take several years to reach sexual maturity, typically around 4 to 5 years. Once mature, adults continue to grow slowly and can live up to 20 years. Spring → Spawning → Summer → Larval growth → Fall → Settling on the bottom → Winter → Slow growth

The orange roughy is a rather solitary species, although it can sometimes be found in small groups, especially during the spawning period. It is not particularly territorial, but it defends its immediate space against intruders. Sensitive to pressure changes, it reacts little to surface noise or light variations, being accustomed to the darkness of the depths. Surface weather conditions have little direct impact on its behavior, although they may influence currents and food availability.

The orange roughy primarily feeds on small fish, crustaceans, and sometimes cephalopods. Young ones mainly feed on zooplankton and small invertebrates, while adults prefer larger prey. In winter, when food availability may decrease, the orange roughy can reduce its metabolism to adapt to the harsher conditions. Its diet varies little throughout the seasons, but it may adjust its hunting habits based on the abundance of available prey.

Fishing for the orange roughy is more a matter of scientific research or accidental capture by trawlers than sport fishing. In spring, the spawning period may make the fish a bit more active, although their habitat depth remains a challenge. In summer and fall, their feeding activity is relatively stable, but they generally remain at depths inaccessible for angling. In winter, their metabolism slows down, and they become less active. Surface weather conditions, such as atmospheric pressure or wind, do not directly affect these deep-living fish.

Since the orange roughy is rarely targeted by anglers, the choice of lures and colors is less relevant. However, for scientific studies or accidental captures, lures in reddish or brown colors may be used to mimic this species' natural prey. The lures should be designed to reach significant depths, and their movement should be slow to simulate the usual prey of the orange roughy.

For bottom trawling, robust commercial equipment is necessary. This includes steel cables, powerful winches, and nets designed to withstand the pressure of great depths. For the rare occasions when the orange roughy might be fished with a rod, a heavy sea fishing rod, with a line over 50 lb, would be necessary to reach and bring up a fish from the depths.

Due to the depth at which it lives, the orange roughy is generally not handled by recreational fishermen. For researchers or commercial fishermen, it is important to handle the fish carefully to avoid damage to internal organs caused by pressure changes. Catch-and-release is rarely practiced, as fish captured at such depths often suffer from barotrauma.

In the deep sea, the orange roughy has few natural predators due to its habitat and thick scales. However, it can be threatened by certain species of deep-sea sharks and larger fish like the roughy. Seabirds do not pose a direct threat due to the depth at which it lives.

The conservation status of the orange roughy is not considered concerning on a global scale, although it is sensitive to pressures from commercial fishing. In Quebec, there are no specific regulations for this species, but sustainable fishing practices are encouraged to avoid overexploitation of deep-sea populations.