Algae are classified mainly based on their pigments (colors).

Main Types of Algae

• Green algae (Chlorophyta): Found in ponds and freshwater. Rich in chlorophyll.
• Brown algae (Phaeophyta): Includes kelp, lives in oceans. Brown because of fucoxanthin pigment.
• Red algae (Rhodophyta): Found in seas, used in food (like agar & carrageenan).
• Blue-green algae (Cyanobacteria): Technically bacteria, but can photosynthesize.