Gutweed

Care Summary

Gutweed (Ulva intestinalis) is a fast-growing green tubular macroalgae and an effective nutrient exporter. It tolerates a very wide range of conditions — high temperatures, low salinity, and elevated nutrients — making it resilient but also potentially invasive. Best kept in a refugium rather than the display tank. Harvest frequently; if left unchecked it can form dense mats that reduce flow and trap detritus. It is relished by tangs, rabbitfish, and sea urchins, making it a useful live food source.