That's really sad news. With them dying so close together it sounds like the ones that didn't appear to be eating really weren't eating anything, not even copepods.
I'm curious as to the cause of their refusal to eat. It could be that mandarins are simply very poor shippers. Lots of WC don't make it either. So perhaps these fish are easily stressed beyond recovery. The long supply chain between the wild and the destination tank could give more chances to "screen out" the ones that don't make it, thus somewhat masking their fragility.
Or perhaps it has something to do with the food they were raised on. Mr Wittenrich raised his first batch on wild plankton, which includes a wide range of prey species for the larvae. But he observed that they could be raised on rotifers alone (though with much higher larval mortality). If ORA raised these mandarins on rotifers alone perhaps that has caused unexpected problems in these young fish. Mandarin larvae in the wild probably eat a proportionally large amount of copepod nauplii and other nutritious prey items. By comparison rotifers have a very low nutritional value, especially the important fatty acids EPA and DHA, unless heavily enriched. EPA and DHA are important to the neural development of larval fishes, among other things. Perhaps the larval rearing foods used lead to weaker neural system development in these fish. With a weak neural system some of them might simply never recover from the stress of shipping.
It could also simply be a matter of not enough screening on ORA's part. Demersal spawners like ORA usually sells typically produce a smaller number of more highly developed larvae. But pelagic spawners like mandarins typically produce large numbers of poorly developed larvae. Perhaps that leads to a large yield of fish but with a larger percentage that need to be culled, and in the wild would be.
Whatever the cause is I hope ORA gets it under control so that they either improve the survival or bring the price down to be competitive with WC. I think aquaculture is the future of this hobby. But it's not going to entice enough people if the fish costs several times what WC do and don't necessarily have better survival.
There is a very good reason internet links (even wikipedia) are not acceptable as references in academic research papers.
