Oceanic brand.... Does it mean the ingredients are oceanic of origin?????
Instead of going through the trouble with hake, and its potential to get messy (as you will have to finely chop it) rather look at your feeding procedure. Feed a little, ensure fish eat it all, then feed a little more at a later stage. If your flow dynamics causes food to be pushed between the rocks, turn off your flow whilst feeding, or increase your clean up crew.