Target feeding is a hit and miss, it depends on the size and verity of clam you are feeding, and what you are feeding it. Under 3†it is generally considered a good idea to (target) feed, after that most clams rely on there zooanthellae for food energy. In addition, clams cannot consume foods over 50 microns and most are carnivores not herbivores. If you use the correct foods in a higher concentration, you will not need to (target) feed. PM myself or Deuce67 about a food I turned him onto, he is very impressed.