Which substrates are commonly used for coral settlement?

The use of terra cotta or limestone tiles for coral settlement is supported by their natural composition and surface characteristics, which create an ideal environment for coral larvae to attach and grow. These materials are biodegradable and tend to blend well into the natural reef structure, providing stability and mimicking natural substrates found in marine environments. The texture and porous nature of limestone and terra cotta facilitate the recruitment of marine microorganisms, which are essential for establishing a suitable habitat for coral.

In contrast, while plastic sheets and nets may be used in some applications, they do not offer the same level of ecological compatibility as natural materials. Wooden planks can result in leaching of chemicals into the water, which may be detrimental to coral health. Glass and silicone materials might provide a smooth surface but can be less conducive to coral attachment compared to more natural, textured substrates, limiting the successful establishment of coral in those instances.