In general, sponges need to be disected and under a microscope with a trained eye to positively identify, however, as with most sponges, you need good water parameters, good flow/circulation, not direct but caotic, and adequate suspended food. Keep us posted on how you do. keeping sponges is surly a learning process. usually not an animal I would purchase, although Ive had sponges in the past. nice looking animal though. good luck with it.
Never Allow Sponges to dry out - air can Kill them.
Keep sponges immersed in water at all times to prevent air being trapped inside the animal. Trapped air is a major cause of death. Avoid placing sponges in areas where they can become smothered by detritus. Blue and purple sponges have symbiotic species of cyanobacteria that require high levels of lighting.
Cant id the snail too blurry of a pic.