Length | Few centimeters to several meters. |
Weight | Varies by species, from a few grams to hundreds of kilograms. |
Body Shape | Typically streamlined for swimming. Some have flat or elongated bodies. |
Fins | Two pairs of fins (dorsal, pelvic, pectoral, and anal fins), and caudal (tail) fin. |
Mouth | Varies by species; can be terminal, superior, or inferior. |
Gills | Used for breathing and extracting oxygen from water. |
Eyes | Vary in size and position on the head. |
Coloration | Varied, often camouflaging to surroundings; may change for display. |
Reproduction | Most lay eggs, while some give birth to live young. |
Senses | Good sense of smell, lateral line system for detecting vibrations, and vision adapted to water. |
Habitat | Found in oceans, rivers, lakes, and ponds. |
Diet | Carnivorous, herbivorous, or omnivorous, depending on the species. |
Lifespan | Few years to several decades. |