Harlequin Grouper

 Quick Care Facts

• Care Level: Moderate   • Temperament: Aggressive   • Maximum Size: 18"
• Minimum Tank Size: 220 gallons   • Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
• Diet: Carnivore   • Origin: Indo-Pacific
• Family: Serranidae   • Species: Groupers   • Aquarium Type: Predatory

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Harlequin Grouper or as they are also commonly known as the Polleni Grouper or Polleni Harlequin Grouper, are a larger Indo-Pacific species that dwells in and around coral reefs and rocky areas. They use the coral reef as protection from larger predatory species like sharks or larger groupers, as well as a place to ambush prey with a quick burst of speed and large open mouth. Harlequin Groupers are a very hardy species, that will quickly adapt to aquarium life provided that it is maintained in a large aquarium with excellent filtration.

This species is best suited for FO (fish only) or FOWLR (fish only with live rock) aquariums with other large aggressive or semi-aggressive fish species. Smaller fish species, crustaceans and many invertebrates will be seen as food items, thus the Polleni Harlequin Grouper should only be considered for aquariums containing only large aggressive fish species.

Harlequin Groupers have a large body (up to 18 inches in length) typical to that of most grouper fish, with a large frontal body that then tapers towards their tail. Their eyes are set forward on their head with a very large mouth and strong pectoral fins. Harlequin Groupers require fairly large aquariums with excellent filtration to accommodate their size and feeding habits. As Harlequin Groupers eat large meals they end up producing a lot of waste products, which means they need excellent filtration (especially biological and mechanical) in order to keep the water quality high. While this species is not harmful to corals, they are well known for quick bursts that will knock over corals or unsecured live rock, etc.

They are best suited for fish-only aquariums as their large size makes them destructive when kept within reef environments, along with the fact that they will eat any fish that it can fit in its mouth and will eat most any type of crustacean. Harlequin Groupers live near the fringes of coral reefs in the wild, they should be provided an aquarium environment that contains both live rock formations and open swimming areas. They do best with other large predatory species (triggerfish, eels, sharks, etc.) or with adult semi-aggressive species (large angelfish, tangs, etc.).

Harlequin Groupers are an aggressive carnivore that in the wild primarily eat small fish and crustaceans. In the home aquarium, they should be fed large marine based meaty items such as shrimp, mussels, clams, chopped fish, etc. While they will consume feeder fish like goldfish or rosies, these items are not very nutritional for them and should only makeup a very small portion of their diet if at all.

Poor quality feeders like Goldfish can also introduce diseases and pollutants into the water as well. The bulk of their diet should be comprised of quality marine meaty foods. Polleni Groupers should be fed daily an amount of food that they will consume within approximately five minutes.