make sure you cover the glass bottom of your tank, and yea baby rbps are pinicky about bright lights....depending on the size of your aquarium, i would get a light size 2x smaller, ex 48" go with 24"...that way light isnt spread so much everywhere
i also think that dim lights make the piranhas look a lot nicer, birhgt likes make their colors fade and soon they look like silver dollars...rbp's can be very frustrating
Put them on a timer with the lights I find Piranha to like routine . clean the tank the same way evry time feed from the same spot exc........
and Piranha will always be skiddish less as thay grow and get use to the "routine" us it live it routine with P's
i'm actually think it's a good idea not to settle into a routine, that way it's not a big deal when you alter the routines. i go out of town alot and work schedule use to alter quite a bit. i don't need to find a fish sitter when i go out of town because they no longer know a routine
mine are still skittish at about 6 inches and especially when feeding. they have started to chill out, but still wont eat if i stand directly in front of the tank