yeah cubans are definitely fearless, temp, pH etc isnt any different than the other big guys, stability is the main thing. i grew some of these guys out awhile back but got rid of them when the big male was about 5in, (am actually about to get one of the females back to see how she does in my tank) but when i had them i had them in with a bunch of other growouts from midas, carpinte, to a festae much smaller (they could have eaten him) but they seemed more interested in food. very personable fish, dont really change in appearance as they mature they keep that brown/white patterning. they definitely weren't ever picked on thats for sure they held their own but i dont remember them really being outright bullies or trying to kill any of the fish either