Chalk bass (Serranus tortugarum)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Perciformes · Family: Serranidae · Genus: Serranus.

Accepted name: Serranus tortugarum · Authority: Longley, 1935 · Taxonomic status: accepted · AphiaID: 273910.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273910 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

Measured values published by FishBase for Serranus tortugarum. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 8 cm · Depth range: 12–396 m · Habitat zone: reef-associated · Body shape: fusiform / normal · Vulnerability index: 10 of 100 · Fishery importance: commercial · Aquarium trade: commercial.

FishBase notes: Found over rubble, silty or sandy bottoms (Ref. 9710). Often in small groups hovering over a patch of coral rubble or an old conch shell (Ref. 13442). Feeds on plankton (Ref. 9710). Synchronously hermaphroditic. Difficult to approach (Ref. 9710).

Source: FishBase species summary (SpecCode 3351) — https://www.fishbase.se/summary/Serranus-tortugarum.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

19,681 georeferenced occurrence records for Serranus tortugarum are published through GBIF from 23 countries or marine areas. The map above plots 51 distinct locations from a sample of 3,000 records, omitting 1 inland record that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: United States of America (18,497); Puerto Rico (810); Virgin Islands (U.S.) (142); Mexico (52); Belize (40).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2388727) — https://www.gbif.org/occurrence/search?taxon_key=2388727&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=273910 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Conservation status (IUCN Red List)

The IUCN Red List assesses Serranus tortugarum Longley, 1935 as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 16759567) — https://www.iucnredlist.org/species/16759567/0; GBIF IUCN Red List category endpoint (taxonKey 2388727) — https://api.gbif.org/v1/species/2388727/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

Serranus tortugarum has a laterally compressed elongate body with a pointed snout which is shorter than the diameter of the eye. It has 3 clearly visible spines on the gill cover, the middle spine being straight. The margins of the preopercle are regularly serrated but there are no spines at its angle. The dorsal fin has 10 spines and 12 soft rays while the anal fin contains 3 spines and 7 soft rays. The caudal fin is truncate. This species shows a variable coloration and patterning and can change the colour and pattern on its body in relation to its environment as a means of camouflage. The typical colour is that the head and body are pale blue-grey, to pinkish brown with 8 narrow, vertical blue-grey bars on the upper body, the most forward just to the rear of the eye and the last one on the base of the caudal fin. Where they are underneath the dorsal fin they extend onto it. There is a row of 2-3 pale blotches on the flanks and the colour of the fins varies from transparent to pinkish. The chalk bass attains a maximum total length of 8.0 cm.

Serranus tortugarum is a species of the western Atlantic Ocean where it occurs from the Bahamas and southern Florida, throughout the Caribbean and along the mainland coast from southern Mexico to Venezuela.

Serranus tortugarum is found over substrates of rock, silt or sand at depths of 2 to 400 m, although it is normally found at depths of less than 90 m. This is a social species that is normally recorded in loose aggregations which have a clear hierarchy. It is a simultaneous hermaphrodite, meaning that each fish has both male and female reproductive organs at the same time. However, self-fertilisation has not been recorded. This species practices egg parceling, which means that long-term partners trade sex roles each time they spawn, maintaining an equity of resource allocation. Chalk bass feed on zooplankton, although larger fish have been recorded feeding on more sizeable crustaceans which they swallowed whole. They frequently hover over sandy or rubble areas of seabed and use a nearby conch shell for shelter.

Serranus tortugarum was first formally described in 1935 by the American biologist William H. Longley (1881-1937) with the type locality given as the Tortugas Islands in the Florida Keys.

Serranus tortugarum occurs in the aquarium trade.

Source: Wikipedia: Serranus tortugarum — https://en.wikipedia.org/wiki/Serranus_tortugarum (CC BY-SA 4.0). Accessed 2026-09-23.