Yep probably dead. I have recently had an outbreak of NTD and two of the neons are MIA. Probably how it spread to the others - diseased fish being eaten. The other casualties, once I realised what was happening, have been hooked out and either euthanised if alive or disentangled from the filter where their corpses came to rest. Still have four left that look OK (its been a week since the last death). I also lost a frog. The betta was bullying it so I moved it to another tank and never saw it again. Since the tank was sealed I guess it died too. Didn't show on the water parameters tho.
