Seahorses not eating one dead? one just wont eat?

[persun87]

Hello i have two kellogi seahorse and have had them for about 4-5 months they have been fine eating frozen food good literaly attacking the feeder lately they dont eat found one dead yesterday and the male still wont eat probably for a few days now. all parameter check good all 0's change water last night just dont get it anyadvice on maybe an illness that may cuase this or how to cure it thanks