Just got some of this guys right now there in there own tank but like to put them in the p tank cause its in the living room so I can see them. At the store they was in the same tank as ps.
If you put 2"exo in with 1.5"Piranha's I would have a ratio of three P's to
one exo . If you do it the other way the exo will harass the hell maby kill
your piranha . Been their done that .
Good luck .