FSS

Problems:

Corals are generally accustomed to stable water conditions, and some elements in the water are converted into complex molecules in the coral tissue, which then perform specific functions in and on the coral. These include, for example, innate defense mechanisms based on complex antiparasitic molecules.

Measures:

In general, important and displayed water values should be adjusted according to the reference values provided. These values have been tested and are effective in thousands of aquariums. While natural values play a role in some cases, they do not always. The aim is to adjust aquarium values to compensate for the insufficient input from natural sources via food, water, and dosing.

Indicator Species:

If the FSS value is too low, it must be determined which element is deficient. The corresponding indicator species can be found in the description of each element:

• Fluoride
• Sulfur
• Strontium

Generally, a low FSS value is associated with an uneven, pale, and less brilliant mucus layer. This layer appears irregular, sometimes thickened, and slightly grayish.

What to Do?

• High Value: In this case, please check the individual elements and adjust them according to the specific guidelines for each element.
• Low Value: In this case, please check the individual elements and adjust them according to the specific guidelines for each element.

Background on the FSS Value:

Corals produce a mucus layer that, in addition to serving as a physical barrier, also contains antimicrobial substances such as AMPs (antimicrobial peptides) and lysozymes. This mucus layer helps to repel pathogens and prevents them from penetrating the coral tissue. These molecules are part of their innate immune system and include both chemical defense substances and physical barriers.

Here are the key molecules that corals produce to protect themselves against parasites and infections:

• Antimicrobial Peptides (AMPs): These small proteins play a central role in defending against infections. They can kill bacteria, viruses, fungi, and even parasites by destabilizing or destroying their cell membranes. Corals produce a variety of AMPs to protect against different pathogens.
• Melanin: This pigment is produced by corals in response to stress or injury. It serves as a physical barrier against invading parasites and pathogens and supports immune defense by producing reactive oxygen species (ROS) that can destroy potential pathogens.
• Reactive Oxygen Species (ROS): Corals use ROS as an important part of their immune defense against pathogens such as bacteria, viruses, and parasites. ROS are highly reactive molecules containing oxygen, such as superoxide anions (O₂⁻), hydrogen peroxide (H₂O₂), and hydroxyl radicals (OH·). These molecules play a crucial role in the coral defense mechanism. A key point here is the ability of corals to use substances with antioxidant effects. This can be achieved through halogens, sulfur, essential fatty acids, and other substances.
• Lysozymes: These enzymes can break down bacterial cell walls. They are part of the coral’s innate immune system and help to control or prevent bacterial infections by destroying bacterial cell wall structures.
• Phenolic Compounds: These organic molecules have antimicrobial properties. They can act directly against pathogens or disrupt communication between microorganisms, preventing the formation of biofilms and uncontrolled proliferation of pathogenic microbes.