I have dealt with a handful of bd so far. I find they can be finicky. Out of 4 pairs we had 4-5 rays that didn’t seem to eat after a 2 hr transport. Perfectly healthy beforehand but stopped eating, heads caved in and spots running.
be on alert, this is full emergency mode. If you don’t get them to eat something soon, it may not recover.
like what others have suggested. Try live food, black worms, guppies, blood worms, earthworms, ghost shrimp. Whatever you can get your hands on. I try the cheapest options first and work my way down the list. You may need to get some metal tongs and try to feed them the live food with that. I have nursed many new rays back to health with this method.
another really good medication to use if you can get your hands on it is bifuran or bifuran 2.We had a snow leopard/ boesmani hybrid that stopped eating for almost 2 months and I thought it was a goner for sure. We did some good wc and dosed with the yellow powder and it started eating. The hip bones looked like they were going to pop through the skin.
good luck.