Information about Flagtail Prochilodus (Semaprochilodus insignis)

[toffee]

Quite intrigued by Flagtails but knows nothing about them. If the tank is 8x2x2:

1. 
   Are they a shoaling type?
2. How many matured Flagtail can that tank handle?
3. Assuming well fed with veggies, Do they still eat aquaplants?
4. Are smaller fishes say tetras save with them?
5. If we go the other direction, instead of small tetras, can they handle mean cichlids like Midas? Would the Mida cause them to shoal more?
6. How fast do they grow if environment is agreeable?
7. How old before they lost the black dots on their body?

Thanks for helping.