Gracilaria parvispora Care Guide
Gracilaria parvispora is a red marine macroalga (Hawaiian ogo) with bushy fronds, valued as tang food and as a refugium plant in marine systems.
Compiled by Aquairi from published sources · Published · Updated
Overview
Gracilaria parvispora I.A.Abbott, 1985 is a red alga of the family Gracilariaceae. The genus Gracilaria comprises red algae with branching thalli; worldwide it supplies the majority of commercial agar and many species are highly palatable to tangs and other herbivorous fish. In reef husbandry it is grown both as fish food and for nutrient uptake.
Taxonomy
- Family: Gracilariaceae
- Genus: Gracilaria
- Scientific name: Gracilaria parvispora I.A.Abbott, 1985
- Class: Florideophyceae; Order: Gracilariales (phylum Rhodophyta)
- WoRMS AphiaID: 374587 (accepted)
Habitat
Gracilaria parvispora is associated with Hawaii, where it is known as Hawaiian ogo. The genus as a whole occurs in warm waters worldwide with seasonal presence in temperate regions; it does not survive below about 10 °C, and its centre of diversity lies in the western Pacific where it is traditionally cultivated for agar.
Aquarium use
In marine aquaria the alga is kept in display refugiums or grazing areas. Its bushy fronds offer a high-value supplemental food for surgeonfish (tangs) and other herbivores, while its growth helps export dissolved nutrients from the system.
Tank requirements
- Water type: saltwater (marine)
- Temperature: 22-28 °C (72-82 °F)
- pH: 8.0-8.4
- GH reference: 8-12 °dGH
- Lighting: medium
- CO2 injection: not required
- Growth rate: medium; height up to ~25 cm
Care and propagation
Gracilaria is propagated by division and benefits from gentle water movement to keep fronds clean. Regular harvesting, roughly every two weeks, both feeds herbivores and maintains nutrient export. The genus is known to be susceptible to the parasitic oomycete Pythium porphyrae, so unhealthy tissue should be removed.
Propagating Gracilaria parvispora (Hawaiian Ogo) by Division
Overview
Gracilaria parvispora, the Hawaiian ogo, is a red macroalga in the family Gracilariaceae with bushy, tubular fronds. The genus Gracilaria occurs in warm waters worldwide and seasonally in temperate seas, with a center of diversity in the Western Pacific, and cannot survive below about 10°C. Gracilaria species generate over 90% of the world's agar and are eaten across Filipino, Hawaiian, Japanese, Korean, and Sri Lankan cuisines.
In the reef hobby Gracilaria is prized because it is highly palatable to herbivorous fish — tangs in particular — and its effective nutrient uptake makes it well suited to aquarium refugiums. Aquarists like growing it precisely because fish enjoy eating it, so it doubles as a living food source and an export tool.
Propagation Method
Gracilaria is propagated by division and fragmentation of its branched fronds. Each separated piece continues growing on its own, so you simply split a healthy clump into smaller bushes. Pieces can be left to tumble freely in a refugium or loosely anchored among rock to grow out.
Step-by-Step
- Pick a healthy, richly colored clump with firm, bushy red fronds.
- Divide it into several smaller branched pieces by pulling or cutting apart the fronds.
- Place the divisions in a lit refugium with moderate, turbulent flow.
- Let pieces tumble freely so all sides receive light, or wedge loosely among rock.
- As the fragments grow, periodically harvest and re-divide to expand the colony.
Conditions for Healthy Growth
- Moderate lighting in a refugium drives steady growth of the red fronds.
- Stable warm marine conditions; the genus cannot survive below about 10°C.
- Effective access to nitrogen and phosphorus, which the alga takes up efficiently.
- Turbulent, tumbling flow to keep clumps moving and evenly illuminated.
- Full marine salinity consistent with its warm-water, refugium-friendly nature.
Maintenance
Harvest regularly by thinning the macroalgae; removing biomass is what actually exports absorbed nutrients from the system. Feed the fresh trimmings to tangs and other herbivores as high-value grazing food, and re-divide retained pieces to keep the refugium colony vigorous.