Caloglossa Beccarii (Caloglossa beccarii) Care Guide
A unique freshwater red alga with flat branching thalli that resemble miniature fern fronds. Under high light, it develops attractive reddish-brown coloration.
Compiled by Aquairi from published sources · Published · Updated
Overview
Caloglossa beccarii is an aquatic plant in the family Delesseriaceae. A unique freshwater red alga with flat branching thalli that resemble miniature fern fronds. Under high light, it develops attractive reddish-brown coloration. Grows slowly attached to hardscape and adds an unusual texture that differs from typical mosses and plants.
Taxonomy
- Family: Delesseriaceae
- Genus: Caloglossa
- Scientific name: Caloglossa beccarii
- Other names: Red Algae Moss
Habitat
A red alga belonging to the family Delesseriaceae, native to brackish and freshwater habitats of tropical Southeast Asia. In nature it grows attached to wood, roots and rock in mangrove margins and lowland streams.
Growth requirements
- Light: medium (≈50-80 PAR at substrate)
- CO2: optional (CO2 improves growth and coloration)
- Temperature: 20-28 °C
- pH: 6-7.5
- GH: 2-12 °dGH
- Substrate: not required (rootless or free-floating)
- Nutrient demand: low
- Growth rate: slow
- Difficulty: intermediate
Placement
- Recommended placement: attached to wood or stone (epiphyte)
- Maximum height: 3 cm
- Trim every: 30 days
Propagation
In cultivation the plant is propagated by vegetative division or fragmentation.
Propagating Caloglossa beccarii (Red Algae) by Division
Overview
Caloglossa beccarii is not a moss or a vascular plant but a red alga, distributed across littoral zones from tropical to temperate waters. The genus is well known for tolerating a wide range of salinity, growing on stones along marine coasts and epiphytically in saltmarsh and mangrove habitats, as well as in freshwater. Its thalli look like tiny branching fern fronds, each carrying a conspicuous midrib formed by a row of elongated cells, and they develop reddish-brown tones under stronger light.
In the aquarium it is prized for being unusual yet relatively easy to cultivate, attaching to hardscape and growing slowly. It tolerates low-end brackish conditions, reflecting its estuarine and mangrove origins.
Propagation Method (Division)
Caloglossa spreads vegetatively in freshwater, so propagation is done by division and fragmentation rather than by cuttings. A clump is broken into smaller thallus pieces, each of which continues branching once anchored. Sexual reproduction is reserved for brackish water and is not needed for home cultivation.
Step-by-Step
- Lift a healthy portion of the alga and rinse it in tank-temperature water.
- Separate it into small branching fragments, dividing where the thalli naturally fork.
- Spread the fragments thinly over the rock or wood you want to colonise.
- Hold them in place with cotton thread, fishing line, or a piece of fine mesh until they anchor.
- Position the hardscape under medium light with gentle flow and leave it undisturbed to attach.
Conditions for Healthy Growth
- Temperature: warm-tolerant, roughly 20–28°C, in line with its tropical-to-temperate range.
- Light: medium light brings out the attractive reddish-brown coloration.
- Flow: gentle, steady current keeps the fronds clean and supplied.
- Salinity: thrives in freshwater but tolerates low-end brackish, echoing its estuarine habitat.
- Water: soft to moderately hard, slightly acidic to neutral; CO2 is not required.
Maintenance
Thin and reshape the colony when it grows out, re-attaching trimmed fragments elsewhere as new divisions. Keep detritus off the fronds during water changes, and ensure light reaches the lower layers so the colour stays rich rather than fading.
Common Challenges
Sudden swings in salinity or temperature stress the thalli. Introduce any change gradually and give the colony time, since visible spread is slow.