Welcome to the site!
Can you post your water parameters (the actual numbers)?
PH, ammonia, nitrites, nitrates, temp and salinity...
Are you buying all these fish from the same store?
I like to do a drip acclimation for an hour or so, this gives me time to fiddle with the tank and get it ready for my new critters.
How much LR
do you have and what is the size of your tank?
That purple tip likes fish and shrimp.