look under neith their gills you should see a few "spikes" coming out from the lower part of the gill.
in True perculas these "spikes are usually black and on the ocellaris clownfish they are orange.
hope that helps.
i would pu the hippo in before the yellow and also i have a royal gramma and i wish i never got him because he dosent like anyone new yo be added to the tank and he hates when my cleaner wrasse tries to clean him.
ya i run skimmer
ph is 8.3
hes been in the tank about 1 1/2 mnths
there is 1 fish larger then him a royal gramma but hes been in there the whole time and he dosnt bother anyone
my blue tang has just begun to breath very deeply
i tested parameters and found out that
ammonia-0
nitrite-0
nitrate-20
dont know what the cause is
temp and salinity are normal