What are white worms the size of large rice in a salt water aquarium?

White worms the size of large rice in a saltwater aquarium are likely either detritus worms or the larvae of marine worms such as bristle worms. These organisms often thrive in environments with excess organic matter and can be a sign of overfeeding or poor water quality. While they are generally harmless and can even be beneficial as part of the cleanup crew, their presence may indicate the need for better tank maintenance. Regular water changes and reducing uneaten food can help control their population.