Individual polyps can have 16-30 tentacles each and are characterized by their brown color, owing to the presence of symbiotic photosynthetic zooxanthellae living inside of them.

[7] This species produces small polyp individuals with a 2 rings of blunt tentacles surrounding their oral cavity.

Their oral disk also has small grains embedded inside of it, leading to an appearance of silvery flecks on the ectoderm of the organism.

[3] Isozoanthus sulcatus uses its tentacles to collect small food particles from its environment and supplements this source of nutrients with symbiotic photosynthetic zooxanthellae.

It has a tendency to open its tentacles when exposed to light for longer than 5 minutes and it is theorized that this behavior is the organism trying to help its symbionts photosynthesize more readily.

When exposed to semi-darkness at a temperature of 23°C for a period of 24h, polyps will expel a thick mucus that contains a large amount of zooxanthellae.

sulcatus contains highly efficient photosynthetic symbionts that are able to produce more than enough of their host's daily respiratory carbon requirements.