I use spinach; I just put it in a cup of water and pop it in the microwave for like 10 seconds to soften it up. I have found that some of my fish find it easier if I stick the clip to the bottom of the tank so that the food is floating up. For some time I just took off the suction cup and set it on the bottom, the clip provides enough weight to keep it pretty stationary. I buy the spinach salad mixes so I could eat some of it and give my fish some of it. But I have just bought a whole head of spinach before.
