Codium sp.
| Care Level | Moderate |
| Lighting | Moderate |
| Water Flow | Moderate |
| Placement | Display or refugium, attached to rock |
| Primary Use | Ornamental & nutrient export |
| Growth Rate | Slow to moderate |
Overview
Codium, often called dead man’s fingers, is a dark-green macroalgae that grows in firm, spongy, cylindrical branches that fork like fingers. It is a handsome, slow-growing ornamental macro that adds structure and deep green color to a display or refugium, with a more substantial, less stringy look than most macroalgae.
Care & Placement
Moderate. Give it moderate light and moderate flow, attached to rock in the display or refugium. It is slower growing and less aggressive than many macros, so it holds its shape and stays put rather than sprawling. Stable conditions and decent water movement keep the branches firm and green.
Uses & Nutrient Export
It offers modest nutrient export as it grows, but like Maiden’s Hair its main appeal is ornamental — a sculptural, deep-green accent. Its slow growth means it exports nutrients more gently than a fast grower like Ulva or Chaetomorpha.
Propagation & Harvesting
Grows slowly, so it seldom needs harvesting. Propagate by dividing a clump and attaching a branch to new rock. Its slow, tidy growth makes it one of the easier display macros to keep in bounds.
Cautions
Some herbivores will nibble the soft branches, so in a tank with heavy grazers it may get picked at. It is slower to recover than fast macros, so avoid letting it get badly damaged or buried. Overall it is undemanding, just not a heavy-duty nutrient exporter.
Frequently Asked Questions
What is Codium (dead man’s fingers)?
It is a dark-green macroalgae with firm, spongy, finger-like branches, grown mainly as an ornamental display or refugium plant for its sculptural shape and deep color rather than for fast nutrient export.
Is Codium hard to keep?
It is moderate — undemanding but slower growing than macros like Ulva or Chaetomorpha. Give it moderate light and flow and stable water, and protect it from heavy grazers that may nibble the branches.
Does Codium export nutrients like Chaeto?
It takes up some nutrients, but far more gently than Chaetomorpha because it grows slowly. Choose Codium for looks and light nutrient uptake; choose Chaeto or Ulva when heavy export is the goal.