* Bleaching: This is the most obvious sign of heat stress in corals. When corals are stressed, they expel the symbiotic algae that live in their tissues, which gives them their color. Bleached corals appear white or pale.

* Loss of tissue: Heat stress can also cause corals to lose tissue. This can make them look patchy or skeletonized.

* Slowed growth: Heat stress can also slow down coral growth. This can make it difficult for corals to compete with other organisms, such as algae, for space and resources.

* Reduced reproduction: Heat stress can also reduce coral reproduction. This can make it difficult for coral populations to recover from damage.

* Increased susceptibility to disease: Heat-stressed corals are more susceptible to disease. This can lead to further declines in coral populations.

If you see any of these signs of heat stress in corals, it is important to take action to reduce the stress on the coral reef. This may include:

* Reducing water temperature: This can be done by shading the reef, or by installing fans or pumps to circulate cooler water over the reef.

* Reducing pollution: Pollution can increase the stress on corals, so it is important to reduce pollution levels in the water around the reef.

* Protecting the reef from physical damage: Physical damage can also stress corals, so it is important to protect the reef from damage caused by boats, anchors, or other objects.

By taking action to reduce the stress on coral reefs, we can help to protect these important ecosystems and the many species that depend on them.