Except for a single East Pacific species, all reside in warmer parts of the West Atlantic, including the Caribbean and Gulf of Mexico.

They are known for engaging in symbiosis with other marine creatures by providing them cleaning service that consists of getting rid of ectoparasites on their bodies.

[2] They have dark bodies with iridescent stripes running from the tip of the nose to the base of the caudal fin.

[2] Except for the East Pacific E. puncticulatus, all gobies of the genus Elacatinus reside in warmer parts of the western Atlantic, ranging from Florida and Bermuda, through the Bahamas, Caribbean and Gulf of Mexico to the coasts of Central America and northern South America (south to Brazil).

[4] Elacatinus are generally carnivorous, with their primary diet consisting of ectoparasites on skins, fins, mouth and gill chambers of their clients.

[5] Some species of gobies exhibit gonochorism and protogynous hermaphroditism, including bidirectional sex reversal.

[7] Protogyny refers to a category of hermaphroditism where female organs develop or mature before the appearance of male product.

[10] Protogynous hermaphroditism in gobies consists of a male reproductive system with paired, secretory, accessory gonadal structures (AGSs) associated with the testis.

[11] While the AGS is almost universally present in male gobies, protogynous females need to develop AGSs for sex reversal to take place.

The AGSs develop from precursive tissues (pAGSs), in the form of bilateral, ventrally localized cell masses, located close to the junction of the ovarian lobes and the oviduct.

[11] Specifically, the ovarian lobes of small-sized juvenile females of these species possess distinctive pAGSs that started to diminish and then disappeared as they approach adulthood.

[7] Elacatinus species usually maintain social monogamy, a system in which heterosexual pairs remain closely associated during both reproductive and nonreproductive periods.

[12] Males and females of Elacatinus forage together, occupying a single cleaning station and servicing client fish in pairs.

[12] Such behavior observed in Elacatinus is attributed to low costs and high benefits for both sexes that result from being paired with a single, large partner.

[12] Intrasexual aggression used as a means to guard mates is proposed as a primary mechanism of maintaining monogamy.

Furthermore, although it differs among species, cleaner gobies tend to live in environments of low population density where distance between potential mates is rather far.

[15] Rather than seeking their clients actively, they remain close to their cleaning station and seldom move more than a meter laterally.

Moreover, such proactive response may serve as a pre-conflict management strategy that might result in safe outcome for interactions with certain predators.

[5] One of the ways Elacatinus signals its clients is through unique blue stripes that distinguish them from their noncleaning sister species; while their noncleaning relatives possess yellow or green stripes that blend well with their sponge dwellings, cleaning Elacatinus spp.

possessing blue stripes deterred or survived significantly more attacks as compared to green and yellow gobies.

This strategy has been proven effective in keeping interspecies mutualism stable, and such cheating behavior is not readily observed in Elacatinus.