I've found they like it most at around 84-86 as I told you - which is pretty cool because most geo's crap out at those temps.
Would make a sweet discus setup if you had a 300 gallon tank to spare.
A harem of the tapajos at the bottom, maybe a 32" tall tank with a shoal of discus up top...
Anyway, remember the large water changes and power feeding high protein content food and you should get at least .5" in growth out of the males every month until they hit around 4" - they can also tolerate severe drops in water temperature during water changes (I would make mine go from 84 degrees to 78 degrees with 80% change).
Don't know why they're so prone to ich, keep em' over 84 and you won't have to deal with it though, they'll start to get HITH if you keep them under 80.
Hooray for giant derail bumps...and absolut vodka.