Like other living creatures, fish must meet certain basic needs for survival. Water, food and shelter are among the most important requirements:
• Water: Fish not only live in water, but they get oxygen from water. They breathe by taking water into their mouths and forcing it out through gill passages.
• Food: Fish must be able to find enough to eat at various life stages, whether they feed on microorganisms, small fish or larger prey.
• Shelter: Fish need a place to hide from predators and to reproduce. Some fish find shelter among submerged aquatic plants and shoreline vegetation, while others hide among rocks, soft sediments, or blend into clear, open waters.
and filtration
