Scientific Name: Caulerpa sp.
Classification: Macro Algae
Common Names: feather algae, green feather algae
Reproduction: Sexual and non-sexual
Color: Green
Growth Rate: Fast
Lighting: Moderate
Flow: Low / Moderate to High
Care level: Very Easy

Appearance:

Caulerpa is a fast growing macro algae.  It is a green algae which sends out runners and will grow leaf like structures that will look more like features.  The ‘leaves’ can grow as large as 4 inches long and ¾ of a inch wide. I find it to be very nice looking macro algae.  But don’t be fooled by its looks. It can quickly spread across your rock and substrate, even chocking out corals or other forms of algae making it a rather invasive macro algae for a display tank depending on your cleanup crew and fish.  Caulerpa is a great algae to grow in a sump or refugium for nutrient removal as it will quickly remove nitrates and phosphates from the water out competing many other forms of algae for these same nutrients.

Lighting Requirements

Caulerpa macro algae will do will with moderate levels of light at the 6500K color temperature range.  However, stronger levels of lighting with lower color temperatures will accelerate growth.  I have even used almost pure red lighting with great results.  I have obtained very good results with high levels of CFL lighting in the 3000K range.  I have also had the best results with a 18 hour photo period followed by 6 hours of no light.

Water Conditions

This is a very hardly algae that will grow in almost any conditions. However, maintaining your water parameters as described in the below link will help to ensure this algae will grow well.  Caulerpa will also do best in a set-up that normally produces around 5ppm of nitrate which would be the exception to the below information.

https://www.reefaquarium.com/2013/the-basics-of-marine-aquarium-water-parameters/

General Care

As this macro algae can reproduce sexually, it is best to heavy trim it back on a regular basis to help prevent this macro algae from spawning in your set-up.  This also will help when using Caulerpa in a sump or refugium as removing some of the algae will also remove the nutrients absorbed by the algae and promote more growth continuing the cycle.

Caulerpa can be a tasty treat for most crabs and tangs so it is important to make sure your current or future tank inhabitants are not known to eat macro algaes.