Comparision of Tisochrysis and Isochrysis

Tisochrysis and Isochrysis are very similar algae that share the same family but branch off at the species and genus level. "In contrast, the T-ISO clone of Isochrysis has only 50 to 70% of the DHA of Isochrysis galbana when grown in side-by-side culture in the same conditions of light and nutrients". This quote shows that Isochrysis actually has a higher DHA content compared to Tisochrysis, making it nutritionally superior. However, Tisochrysis has a thinner cell wall and is more tolerant of higher temperatures than Isochrysis, making it a preferred species over it's cousin.

Tisochrysis has also adapted to the Polynesian islands in Taihiti, most likely explaining it's tolerance for higher temperatures. At Orr Biologicals, we culture Isochrysis galbana because we want algae with the highest DHA possible.

Isochysis galbana is renowned in aquaculture for it's extremely high DHA content (Docosahexaenoic acid) and is only rivaled in terms of nutrition with Pavlova Lutherii. It is a small microalga that ranges from 4-6 microns in size, making it a suitable microalgae for Nauplii stages of copepods and bivalve larvae in the D hinge stage.

This marine haptophyte can be stressed under certain conditions to increase lipid content. Two examples of this are cold and nitrogen deprivation stress. When Isochrysis is exposed to these factors, it starts to store energy in the form of lipids (golden fats) that can be used to survive what it thinks are stressors. We as scientists can harness this trait by shocking the phytoplankton, not enough to kill it, increasing lipid levels.

“Part 5 Hatchery Operation: Culture of Larvae Basic Methodology, Feeding and Nutrition, Factors Influencing Growth and Survival, and Settlement and Metamorphosis.” The Hatchery Culture of Bivalves: A Practical Manual, www.fao.org/4/y5720e/y5720e0a.htm#bm10.2.1. Accessed 04 Apr. 2026.