- Filter - A porous device for removing impurities or solid particles from a liquid or gas passed through it.
"an oil filter" - Gill slits - Any of a series of openings between the gill arches of a fish, through which water passes from the pharynx to the exterior, bathing the gills in the process.
- Migrate - moving of an animal, typically a bird or fish move from one region or habitat to another, especially regularly according to the seasons
- Passive - Feeding on particles by removing them from suspension
- Solitary - Done or existing alone