The largest producer of calcium carbonate (aragonite) of the global ocean: is a Limestone Unicellular Seaweed !!!
About 75% of coral sand in the world is produced by twenty species of Halimeda. Corals come in second. Hard to believe that algae can produce over 125 pounds of sand: per 100 square yards of Ocean floor ... per year.
In a SBMarine tank; Halimeda reproduces sexually. This reflects quality parameters that ensure the development of all types of corals; including LPS & some SPS corals. The main advantage of Halimeda, compared to Caulerpa, is that Halimeda's sexual reproduction does not automatically put the tank’s chemistry and it’s inhabitants in danger every time it occurs.
We witness here: all stages of Halimeda development. Top/center: a new segment (whitish). Left: three young fronds. Right: the characteristic green of healthy fronds. Center and bottom left: the loss of pigmentation (discoloration) due to release of spores. The dispersion of gamete capsules follows. What remains is calcium carbonate ...
The size of the fronds is not the factor triggering sexual reproduction. It can occur even with young shoots. We clearly see gamete capsules (dark green) that will be dispersed quickly.
(48 hours approx.)
Unlike Chaetomorpha which is eaten by many surgeons and other reef grazers... and Caulerpa which is eaten by almost anything that swims, crawls or jumps ... Halimeda does not really have enemies, except the Green Emerald Crab (Mithraculus Sculptus) and perhaps Urchins. If the production of Halimeda is important; do not deprive Mithrax of a delicacy to its menu :) However Halimeda is a prized trophy sometimes hard to find and more expensive than other algae... Once acclimatated to it's tank: Mithrax is hard to extract !! Don't expect picking him up on his rock to transfer him to another tank... You might end up pulling up the 10 pound rock under him !! This could seriously damage or hurt Mithrax.... So always pick up the rock with it's passenger to move it around. Mithrax has an incredibly powerful grip and won't let go !!! (Even tiny 1/2 inch specimens)
Yup !! Seems Oscar was here...
Halimeda provides refuge in addition to it's bio-chemical benefits. One small bunch is great: but a tankfull is better !!
The advantage of the Gendered Reproduction of Halimeda in aquarium: is that the seedlings will tend to develop directly on the rocks. creating a natural setting. Another benefit of this spectacular Seaweed is that it also tends to grow in low light. A feat difficult to achieve when trying to establish a fragment !!
There are over twenty different species of Halimeda. Most of those offered to Aquarists have become invaluable.
This piece developped from the skeleton of a segment... rather rare.
Halimeda can be fragmented occasionally to start new colonies. Some recommend to place them in the sand (according to species)... You can also use a small rock with a large enough hole to allow water circulation at it's base. The lite green segments here show a normal growth.
New segments are always off-white.