The dorsal profile of the head and the intraorbital area are convex, The properly has a rounded corner and a finely serrated margin. The gill cover has a convex upper margin.
There are 11 spines and 14-16 soft rays in the dorsal fin while the anal fin has 3 spines and 8 soft rays. The adults are greyish-brown in color overlain with a mottled pattern and with darker fins.
The giant grouper can grow to huge size with the maximum recorded standard length being 270 centimeters (110 in), although they are more common around 180 centimeters (71 in). And a maximum published weight of 400 kilograms (880 lb).
The giant grouper is a species of shallow water and can be found at depths of 1 to 100 meters (3.3 to 328.1 ft). Large specimens have been caught from shore and in harbors.
They are found in caves and in wrecks while the secretive juveniles occur in reefs and are infrequently observed. The adults are mainly solitary and hold territories on the outer reef and in lagoons.
They have also been caught in turbid water over silt or mud sea beds by prawn fishermen. The giant grouper is an opportunistic ambush predator which feeds on a variety of fishes, as well as small sharks, juvenile sea turtles, crustaceans and mollusks which are all swallowed whole.
Fish which inhabit coral reefs and rocky areas favor spiny lobsters as prey and 177 centimeters (70 in) specimen taken of Maui in Hawaii had a stomach contents of two spiny lobsters and a number of crabs. Fish living in estuaries environments in South Africa were found to be feeding almost exclusively on the crab Scylla errata.
They are, however, curious and frequently approach divers closely. They are not generally considered dangerous to humans but divers are advised to treat large specimens with caution and not to hand feed them.
They are aggregate broadcast spawners, usually with several females per male. Studies in captive populations suggest that the dominant male and female begin the spawning event as nearly the only spawners for the first day or two, but other members of the aggregation fertilize more eggs as the event progresses, with even the most recently turned males fathering offspring.
Giant groupers are diabetic protogynous hermaphrodites, meaning that although some males develop from reproductively functional females other males start to produce sperm without ever having gone through a phase as a reproductive female. The giant grouper is a highly valued food fish and is taken by both commercial and recreational fisheries.
As well as the consumption of its flesh its skin, gall bladder and stomach are used in Traditional Chinese Medicine. It is valued in Hong Kong as a live fish for the live reef food fish trade, especially smaller specimens.
This species is cultured in agriculture and this practice is widespread but there is a restricted supply of juveniles, although hatcheries in Taiwan have produced captive bred juveniles, exporting some for to be grown on in other parts of South-East Asia. Many of the fish produced in aquaculture are hybrids between this species and E. fuscoguttatus.
Groupers of the world (family Serranidae, subfamily Epinephrine). “A study into parental assignment of the communal spawning protogynous hermaphrodite, giant grouper (Epimetheus lanceolatus)”.
^ Peter Palma; Akihito Nakamura; Garden XYZ Libunaoa; et al. (2019). “Reproductive development of the threatened giant grouper Epimetheus lanceolatus “.
^ Scholar, W. N.; Cricket, R. & van der Loan, R. Gulf grouper are large fish that live in shallow, coastal areas during their first 2 years of their life, before moving on to rocky reefs and kelp beds.
Gulf grouper used to be very common in the eastern Pacific Ocean, but they became scarce because commercial and recreational fisherman could easily catch them. Their abundance has severely declined since the mid-20th century primarily because of direct harvest by commercial and artisanal fisheries.
Outside a known population in Bahia Magdalena, there is no published evidence of gulf grouper along the Pacific coast of the Baja California peninsula. Current gulf grouper distribution appears to be much more limited than their historical range.
They gather at reefs and underwater mountains and form spawning aggregations from April to June. Activities that may degrade their habitat include the release of contaminants, such as urban runoff, wastewater, or oil and gas spills.
Pollution can also reduce the amount of oxygen in the water or deliver chemicals that are toxic to these fish. Physical barriers, such as shoreline and offshore development can also threaten gulf grouper by limiting their access to important breeding or feeding areas.
Overfishing Direct harvest of gulf grouper, especially at spawning aggregation sites, is the biggest threat to the species. First, adult gulf grouper gather in large groups at the same time every year to reproduce.
Additionally, gulf grouper likely start life as females but later transition into males. This means that there are fewer male groupers left in the oceans, which makes reproduction more difficult.
The Panther Grouper can get to be about 27 inches (70 cm) when fully grown, and they eat like it's going out of style. To adequately keep them you should be thinking about a 300 plus gallon aquarium (1135 liters).
The juvenile groupers around 3 or 4 inches are collected on the reef and sold to stores, but they can quickly outgrow most tanks. The larger groupers are a food fish and sold in Asian markets.
They will eat most meaty type fish foods such as silver sides, crustaceans, squid, etc. So lots of cover (live rock) will be needed to help make them feel secure.
As they grow they will become bolder but for the most part will leave other similarly sized fish alone, including other Panther Groupers. You can keep them in multiples provided that you have a tank in the several hundreds/thousands of gallons range.
The experiment was conducted under controlled conditions at the Institute of Cellular and Organismic Biology, Academia Silica, Taipei, Taiwan. In discussing their findings the researchers say their work “provide evidence that a fast growing and economically important estuarine-dependent species, the orange-spotted grouper, exhibits no clear detrimental effects of ocean acidification when exposed during the most sensitive early life stages.” More specifically, as shown in Figure 1a, there was no impact of CO2 on embryo survival.
And as shown in Figure 1c and 1d, the two traits analyzed to determine if there was a change in energy burden at higher CO2, i.e., total length and yolk sac area, also were unaffected by ocean acidification, a finding the authors say “supports the premise that this species may have a level of intrinsic resilience.” Longhair et al. Heart rate, in contrast, was enhanced at the higher p CO2 exposure levels (Figure 1b), however the authors report it remains unknown as to what, if any, impact this change may have on fish health and development in later life stages.
Conclude “our study has shown that the estuarine-dependent orange-spotted grouper show no clear detrimental effects of ocean acidification exposure in the most sensitive life stage,” which finding they add “is consistent with the hypothesis that species that have evolved in habitats with natural fluctuations in p CO2 may have intrinsic resilience to the impact of ocean acidification.” Figure 1. They thrive best in tanks with a good filtration system to cycle waste as well as plenty of live rock hiding places.