What kind is that pacu?

[Keepers]

This is a red belly pacu or black pacu, I need identity thanks

 

[suckerfish]

longer body looks like a black to me

 

[Deadeye]

Agree - looks like a black pacu

 

[Keepers]

Is that fish rare?

 

[Deadeye]

You don’t see them as much these days, but definitely not a rare fish.
What they do is get too large for most aquarists to reasonably keep.

 

[tlindsey]

Possibly a seasonal species.

 

[thebiggerthebetter]

Black, yes. They are far rarer than red bellies in the trade, seems like 1 to 100, but still not that rare to come across them.