Red Grape Algae

Botryocladia botryoides

Also known as Red Grape, Red Grape Caulerpa (misnomer), Red grape kelp

SaltwaterMacroalgaeCuttings

Red Grape Algae (Botryocladia botryoides) — Golfopolikayak · CC BY 4.0

Care at a glance

Light: Medium light
CO2: No CO₂ needed
Growth rate: Medium
Placement: Midground
Type: Macroalgae
Temperature: 73–81°F (23–27°C)
pH: 8.0–8.4
Max height: 4.7 in (12 cm)
Spread: 5.9 in (15 cm)
Nutrient uptake: Water column
Growth region: Submersed
Difficulty: Easy
Origin: Warm temperate and tropical seas of the Atlantic and Mediterranean
Family: Rhodymeniaceae

Overview

A hardy, decorative red macro that does double duty as a display accent and a nutrient sponge. It prefers medium light and moderate flow; too much light pales the grapes, so easing off the intensity keeps them a rich red. Anchor it to rock or shell in the midground where its bunched vesicles show, and it grows steadily without taking over the tank. Like other macros it draws nitrate and phosphate from the water, and the grapes are tasty enough that some grazing fish will pick at them.

In the wild

A striking red macroalgae that forms clusters of small, fluid-filled, grape-like vesicles on branching stalks. It grows on rock and shell in warm coastal waters and stays compact enough for nano and reef tanks without overrunning them.

Good to know

Botryocladia botryoides is a red alga in the family Rhodymeniaceae. Its ornamental appeal comes from hollow, sap-filled bladder-like segments that resemble bunches of grapes. Despite the trade name Red Grape Caulerpa, it is not a Caulerpa and carries none of that genus's go-sexual crash risk. It spreads by fragmentation and can be attached to rock with glue or line.

Did you know

Each little grape is a hollow sac filled with fluid, so a healthy cluster looks and feels like a tiny bunch of translucent red bubbles rather than a solid frond.