When you have fish which are difficult with their food or you just want to give them a treat, the Australian Black Worms, is a great choice.  Black worms naturally occure in aquatic enviroments.  These Australian Black worms are cultivated and then dried in a special way to maintain their oil and their dietiery goodness.  High in protein, which makes this a great food for fresh and marine tanks.  No need to keep in the fridge or freezer.
 
This food will not cloud your water if used according to the instructions.