I guess it's chinese perch season right now since I'm seeing them at that size in hong kong and in us. As all of us that have kept that em before has observed, I think I can safely say that these cperch are one of the biggest swimming stomachs around. They can really eat something their own size.
On a side note though, since it is food fish here in hk, I had a chance to taste one.... Gotta say,it's the best tasting fish !!!! Not saying you should eat your perch though, it looks better live than on a plate if you grew it out and get attached to it's personalities
Have fun!!!! Get it trained on some pellets or tilapia bits though, or else you'll go broke on buying feeders.