Hi,
I have a little experience with that fish and I'll get two new 5" in 4-5 weeks.
This serrasalmus swims a lot in comparison with other serra. species ans needs a good powerhead ; I use a 1000g/h for a 50" long tank.
The fish is really agressive and fast. It's sometimes hard to feed this species with dead food but it accepts Atherina boyeri without too much difficulties.
''Black mask'' variant is more attractive, in my opinion, than the ''redthroat'' one but both are really nice fishes.
I recommand a 50g for 4-5" fish, 75g for a 6-8" and a 100" for 8"+, always with a large floor surface.
Hope it will help...
Best regards.