It is a haddoni. It is also bleached. It will need super stable water parameters, strong lighting, and will need to be fed small pieces of shrimp for a while if it will eat.
also, how old is your tank? Haddonis do not do well in newer tanks and need a ton of filtration, as their waste can be quite large. Also, you tank needs to have some finer sand in it. They like to bury their foot and attach to the glass if they can.
as for being aggressive, they technically aren’t aggressive. They don’t hunt fish. Normally easily startled or overly curious fish are the ones that get eaten. These guys have been in a mixed reef for 3 years and have only claimed one fish that got feisty and tried to steal the shrimp that was being fed to it.