Three of them are eating bloodworm and occasionally a bit of white bait when they take it. One of them won't eat anything that doesn't move, I think he's the one your noticing. I hoped he would copy the others and eat bloodworm but no luck as yet. I can only get him to eat worms or white bait when I drop it by the filter outlet. Even then it's still hard to get him to eat. I guess he want's live fish but as you know that's not really do-able in the UK.
Any tips would be great, suggested foods etc...