Peace lilies, also known as Spathiphyllum, are a popular choice for aquariums due to their attractive white flowers and lush foliage. However, these plants can be quite sensitive to environmental conditions in the tank and may start wilting if they don't receive the right care. The most common cause of wilted peace lilies is too much or too little light exposure. If your peace lily is placed in direct sunlight or near bright lights without any shade protection, it will quickly wilt from overexposure. On the other hand, insufficient lighting can also cause your plant to become weak and droopy. Improper water quality can also contribute to wilting leaves on a peace lily; make sure you're using clean water with no chlorine or other toxins that could harm your aquatic plants. Lastly, keep an eye out for pests like snails which feed on soft tissue such as those found on the leaves of peace lilies; removing any infestations promptly should help get rid of this problem before it causes significant damage to your aquarium's inhabitants!