i've seen people keep fish with p's (rbp's) for 2-3 years and i've seen people get there fish eaten in 2 seconds. it all depends on the fishes personality. BUT you must realize this EVERY SINGLE FISH you put with p's WILL DIE, yes they will die EVENTUALLY at some point will be eaten. if you want a species to last your best chances are to wait till your p's are over 5 inches, then you can put liek 50 neon tetra's with them and they will live for a long time becuase they are fast and the p's dont care to eat them becuase they are so small.