Elacatinus puncticulatus
A cleaner goby with vivid red and blue head coloration.
Elacatinus puncticulatus is a goby found in the eastern central Pacific Ocean, ranging from the Gulf of California down to Ecuador. It lives on rocky or coral reefs at depths between 1 and 21 meters, often alongside the sea urchin Eucidaris thouarsii. Its bright colors and non-aggressive nature make it a common species in the aquarium trade.
This fish belongs to the genus Elacatinus, which typically has seven spines, 28 vertebrae, a compressed skull, and transparent fins. E. puncticulatus stands out as the only species in the genus lacking scales on its head and body. Its head displays strong red and blue coloration, while the body is striped yellow and black, with a dark horizontal stripe behind the eye. The blue stripe near the head is thought to help attract client fish for cleaning. The species is sometimes divided into two clades, with further subclades, based on differences in color and genetics. These variations likely arose from oceanographic processes and habitat gaps that separated populations over time. Depending on location, the head, body, and eye-stripe colors can shift from red to a more yellow-orange.
Males reach about 30–40 mm in length, while females are smaller at 22–27 mm. This size difference grows with increasing latitude. As a facultative cleaner, E. puncticulatus has a terminal mouth position typical of the genus, but it also has heterodont dentition—multiple tooth types—which sets it apart from dedicated cleaner species in the genus.
The species lives along the continental shore of the Tropical Eastern Pacific, from the southern tip of the Baja Peninsula to southern Ecuador. It stays in the subtidal zone down to 21 meters, on rocky or coral reefs. These reefs host cleaning stations, where the fish’s bright blue head coloration helps attract clients and feed on ectoparasites. E. puncticulatus is the only Elacatinus species not found in the Atlantic, and one of just two in the Tropical Eastern Pacific. Its distribution is limited by habitat gaps, such as two muddy stretches of shoreline.
Before spawning, males court actively. They shift from their usual red and blue head to a gray head with yellow and black body. A day before spawning, males move their pectoral fins to clean the burrow and breathe heavily to signal readiness. Females show strong red and black colors, turning pale three days before spawning.
Quick Facts
- Family
- Gobiidae
- Depth range
- 1 to 21 m
- Male size
- 30–40 mm
- Female size
- 22–27 mm
- Eggs per spawn
- ~150
- Hatching time
- 168 hours post fertilization
Facts from the source article.
Lore & Background
Elacatinus puncticulatus is a member of the genus Elacatinus, which comprises 25 species characterized by seven spines, 28 vertebrae, a compressed skull shape, and transparent fins. It is the only species in the genus that lacks scales on the head and body. The species displays strong red and blue coloration on its head, with yellow and black striped body markings and a dark horizontal stripe behind the eye. The blue stripe near the head is thought to attract clients for cleaning. Variations in coloration and genetics have led to the recognition of two clades, with subclades, believed to result from oceanographic processes and habitat discontinuities.
E. puncticulatus is the only Elacatinus species not found in the Atlantic and one of only two in the Tropical Eastern Pacific. Its distribution is shaped by habitat discontinuities, including two muddy sections of shore within the TEP. The species lives primarily between the subtidal zone and 21 m depth on rocky or coral reefs, often in association with the sea urchin Eucidaris thouarsii. It is a facultative cleaner, feeding on ectoparasites and cellular debris, and displays heterodont dentition, which differentiates it from obligate cleaner congeners.
Reader's Guide
Elacatinus puncticulatus holds significance as a facultative cleaner goby that maintains cleaning stations on coral reefs, attracting both non-predatory and piscivorous client fish. Its bright blue head stripe is considered an adaptation to signal cleaning services. The species exhibits size differences between sexes, with males reaching 30–40 mm and females 22–27 mm, and this disparity increases with latitude. Its role as a cleaner also influences its morphology, including a terminal mouth position and heterodont dentition.
In the aquarium trade, E. puncticulatus is commonly kept due to its bright coloration, calm disposition, and ease of domestication. It is not listed under CITES species-specific requirements and is referred to as marine tropical fish in trade reports, which can complicate regulation and study of its endangerment status. The species produces benthic eggs that hatch into pelagic larvae after about seven days, with approximately 100 of the 150 eggs per spawn surviving to hatching. Males exhibit parental care, cleaning eggs before and after hatching, though pre-hatch cleaning can cause up to 50% egg loss.
Did You Know?
- Elacatinus puncticulatus is the only species in its genus that lacks scales on the head and body.
- Males display a gray head and yellow and black body coloration during courtship, instead of the usual red and blue.
- The species produces around 150 eggs per spawn, but only about 100 hatch.
- It is one of only two Elacatinus species found in the Tropical Eastern Pacific.
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