help pink tailed trigger needs help

[=FC=Carbonizer]

i bought these from buy and sell they were already in tank
i kept water from old tank
brought home all coral and rock and reset up tank
did 20 % water change for first 3 days
now i do one bucket (14quarts-3.5 gals) per day

i went to j&l today and bought cupramine(seachem) added 7 ml,
i also bought a fluval 404 canister and extra carbon which i will set up and run to remove copper next week
also when to big als and bought a vortex diatom filter which is up and running.
hopfully this works
oh yea the fish were raised together and get along great'
the guy i bought them from only fed them sand eel's(silversides)
is there anything else that i should feed them,i threw in 6 live clams
and they really when to work gone in 2 days,now they try to steal the empty shell from each other(really quite funny to watch)
les