Physical & structural characteristics: Have particularly large eyes, and acute senses of smell and hearing. The common goldfish has two sets of paired fins and three single fins. They also lack scales on the head.
Behavioral characteristics: In the wild, goldfish like to stay in groups. They also aren't particularly aggresive
Natural habitat - water which is a little thick and muddy. Also found in stagnant backwaters. Originally from China
Ecosystem it invades - ponds, lakes and streams