Sorry to hear that... I have very two large Lennardi's in my tank 3 year old well stocked and healthy 250g tank. Have had them for over a month and I never see them feed, especially with the others. Not sure what on earth they are feeding on but seem happy and healthy full reasonably full belly's on inspection although they sleep A LOT. I mean, I might see them out for an hour a day. I wonder if that's because they are conserving energy from lack of food? I have tried everything from burying prawns and pellets in the sand to spread feeding mysis with the other fish. They just look at it and swim past, don't even give it a glance. The prawns I bury general get eaten by my cleanup crew or the bristle-worm I have living in the rocks. Shop i got them from has a great reputation and said they were feeding on small prawns buried in the sand for weeks before he put them out on show.
Anyone have any suggestions?