Sea grapes

Caulerpa lentillifera

Also known as Green caviar, Umi budou, Sea grape caulerpa, Lato

SaltwaterMacroalgaefragmentation

Sea grapes (Caulerpa lentillifera) — djpmapleferryman · CC BY 2.0

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Growth rate: Fast
Placement: Background
Type: Macroalgae
Temperature: 73–81°F (23–27°C)
pH: 8.0–8.4
Max height: 3.9 in (10 cm)
Spread: 15.7 in (40 cm)
Nutrient uptake: Water column
Growth region: Submersed
Difficulty: Easy
Origin: A marine green macroalga of shallow tropical Indo-Pacific lagoons and reef flats, spreading over sand and rubble by creeping runners.
Family: Caulerpaceae

Overview

Wedge it into rubble under moderate light with gentle flow, and it will spread quickly while pulling nitrate and phosphate out of the water. Harvest it regularly and keep it well lit, because a stressed Caulerpa clump can suddenly go sexual, turn white, and dissolve, dumping those stored nutrients back into the tank. Many reefers run the refugium light on an opposite or continuous cycle to keep it stable.

In the wild

Caulerpa lentillifera is a bright green marine alga made of round, grape like beads strung along creeping runners. It grows fast and is best kept in a sump or refugium, where it exports nutrients rather than crowding corals in the display. The dense beads also give copepods and other tiny creatures a place to shelter and breed.

Good to know

Like other Caulerpa, the whole alga is essentially one giant cell with many nuclei and no internal walls, letting sap flow freely through its runners and beads. It grips the bottom with root like holdfasts called rhizoids rather than true roots.