Yellowline Goby (Elacatinus figaro) saltwater aquarium fish portrait

The Yellowline Goby is a diminutive cleaner goby with an elongate, scaleless body, a dark base color, and a pair of vivid yellow dorsolateral stripes that run the length of the fish. A bright yellow marking on the snout completes the pattern and makes this species instantly recognizable in a crowded reef display. It is endemic to the southwestern Atlantic along the Brazilian coast, where it occupies coral and rocky reefs and services client fishes at established cleaning stations. Published maximum sizes vary somewhat between references, though roughly 2 inches is a reasonable expectation for an adult.

Adult housing can be modest. A marine reef or fish-only system of at least 10 gallons is sufficient, provided the layout includes generous rockwork with caves and crevices the goby can retreat into and perch upon. A sand bed is worthwhile, since it supports the minute crustaceans this fish will pick at between feedings. Because small gobies are capable jumpers, a secure cover or tight-fitting lid is strongly advised. The reviewed material does not specify a particular flow regime or a mandatory system age, so standard reef conditions with stable chemistry and abundant hiding structure will serve the fish well.

In the wild, this carnivore makes much of its living by removing material from the skin and fins of larger fishes. Gut content studies from multiple sites identified parasitic isopods and copepods, free-living copepods, cyprid larvae, fish scales, gastropods, and diatoms, with ectoparasites accounting for roughly half of the identifiable items. That mix of grazing and cleaning explains why the species adapts so readily to prepared aquarium fare rather than depending entirely on host fishes.

Offer small meaty items sized for a tiny mouth: cyclops, baby brine shrimp, mysis, and finely chopped shrimp, clam, scallop, krill, or marine fish flesh, supplemented with appropriately small frozen and dry foods. Feeding once daily is appropriate. A newly introduced individual that hesitates to eat often responds to fortified live adult brine shrimp. If the goby is actively cleaning tankmates, treat that as a supplement rather than a substitute for direct feeding.

Cyclops Baby Brine Shrimp Mysis Shrimp Finely Chopped Shrimp Chopped Clam Chopped Scallop Krill Marine Fish Flesh
This is a peaceful, station-keeping fish that spends much of its day perched on rock and coral before darting out to service passing clients. Wild individuals are found alone or in loose groups of up to six around coral heads, algae-covered rocks, sponges, and the shelter of sea urchins. In the aquarium the species is unobtrusive and confident once settled, and larger fishes generally recognize and tolerate its cleaning attentions. Conspecifics can squabble, however, so do not assume that a group will coexist peacefully in a confined footprint.

Choose calm companions. Aggressive, fin-nipping, and predatory fishes such as groupers, dottybacks, and triggerfishes are poor choices, since cleaner coloration does not reliably protect a 2-inch goby from a hungry predator. The species is reef safe and is not documented preying on corals, clams, shrimp, crabs, or snails, making it a sound addition to mixed reef displays. Guidance on invertebrate compatibility is not entirely consistent across references, so observe interactions with very small ornamental invertebrates when first introducing the fish.

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FAQ

Frequently Asked Questions

About the Yellowline Goby

  • What is the minimum aquarium size for a Yellowline Goby?
    A 10-gallon aquarium is the minimum recommended for an adult. Rockwork with caves and crevices matters more than raw volume for this species.
  • Does this goby need a larger fish to clean in order to survive?
    No. It readily accepts small frozen and dry aquarium foods and thrives without a host fish, though cleaning interactions can supplement its diet.
  • Can a Yellowline Goby be kept with aggressive or predatory fish?
    It is best housed with peaceful tankmates. Cleaner recognition may temper aggression from some larger fishes, but predators and fin-nippers such as groupers, dottybacks, and triggerfishes can still eat or harass it.