That's great, thank you both for your replies.

I was told in the pet store that bloodworms were the sole food and that I wouldn't need anything else, as usual this might come down to experience on his part which is contradicted elsewhere; I have seen numerous different approaches but it makes more sense to keep a varied diet. I got some krill, brine shrimp and other frozen worms and will alternate in small batches on alternate days. Thinking about it, it is unlikely they would be able to eat every day in the wild so feeding alternate days will not harm him. I also will just keep the one for now - my book on ADF said the 17L was a good size for two, but if that's not the case, I can see how he might have been a bit stressed out as well.

Ok, going to try and feed him this evening, thanks again for your posts -
matthew