Hydracoral is a stationary alien unit in Civilization: Beyond Earth Rising Tide. They can be cleared out for an XP bonus. Hydracoral have three levels: * Level 1: File:20xStrengthBE.png 10 * Level 2: File:20xStrengthBE.png 18 * Level 3: File:20xStrengthBE.png 32 Ranged units are better choices for clearing these out. Melee units, like Patrol Boats will take damage, whereas hydracoral can not strike back against ranged units. This being said, attacking hydracoral will increase alien anger.