As it is said in Bhagavad Gita, whenever there is a decline in righteous and wherever there is a predominance of unrighteousness, the Lord Vishnu incarnate on earth each time the mankind is in danger or when evil and tyranny overpowers righteousness..
The 10 avatars:
1. Matsya, 2. Kurma, 3. Varaha, 4. Narasimba, 5. Vamana, 6. Parashurama, 7. Rama, 8. Krishna, 9. Budda, 10. Kalki.
Weight : 70 - 120 gms/each avatar, Height - 6.5 - 7 cms/ each avatar.