In this paper obligatory and facultative partnerships between fishes and sponges are described. Sponges are sessile filter-feeders with simple cellular structure. Despite the vulnerability and inadequacy of the sponge defense mechanism, they successfully avoid predators. They form associations with different groups of invertebrates and fish, living on the surface and in interior of the sponges. These organisms have certain structural adaptations to life within the sponge, the most important of which is small size. Little is known on feeding of fish in the obligatory associations with sponges. Symbionts occupy sponges led by differences in sponge color. The lack of suitable sponges in certain areas result in the lack of the fish species living in the community with sponges. In addition to the obligatory relationship, various fish use sponges as the well protected and highly effective incubators of their eggs. A total of 20 nonobligatory sponge symbionts have been classified, which spend at least a portion of their lives in tubular sponges. Most of the facultative relationships between fishes and sponges are poorly understood.