I feed similarly to Bill - pumps off, target with a syringe, or place meatier chunks directly with a skewer. I do the same for my bubble and acan. The acan and the bubble are greedy little buggers and will eat anything any time, but I find it helps to prime the frogspawn by adding a little food juice (from thawing my frozen food) to the tank 10-15 minutes prior - tentacles extend, 'mouth' opens, and it holds onto more of the chunks. I learned this method the hard way by losing a hammer that was tough to feed; it looked great for six months or so, but ended up losing it.
Tim