its no problem,my argentea is smaller than my pearsi but my bocourti is bigger,so he focuses most of his attention on the bocourti(sparing partners)and that lets the argentea eat all the food. Pearsei seem to do well with different size tank mates the aureus should do great to fast for them to be bothered. I have kept mine with silverdollars,t. passiones,and eartheaters with out much problem. The biggest problem i had was with a blackbelt(fought hard all the time had to move the blackbelt) nicraguense(the pearsei killed him) and green terror(also killed)but now as he has gotten older he has seemed to accept tank mates really well as long as he has enough room to stay to himself hen he doesnt feel like being bothered,they are a mellow fish most of the time but can put up a good fight when they want too.
My current setup is a 180
stock:
pair of bocourti(14 inche male,10 inche female)
pearsei(13 inches)
urau(12 inches)
large eather eater(7 inches)
gold severum(7 inches)
pair of argentea(male 7 inches,female 5 inches)
this stock has worked the best so far,no major agression,this whole setup will be moved to a 300 gallon by may(already have the tank,just working on filtration)