I'm with Ooulophilia on this (and I am grateful to hear the dusky survives better as well) - these fish are wonderful when healthy but even with the best of care, survival is really dismal. They get stressed out very very easily, so your tankmates are critical here too. If I ever try any (dusky) jawfish again in the future, I will make sure there are no other bottom fish or pistol shrimp. Also, midwater fish need to play nice too; blue spots are fragile. I do think a mesh top is fine, though you will want the mesh to be fine as they are expert jumpers. Once they are happy in their burrow they don't really jump much though (but the odd stress event cannot be ignored). You have to target feed them twice a day. Anyway, I had one for about 3 months and he was my favorite fish ever, but one day he covered his burrow with a big piece of coral and never reappeared; I think he was ill and I think that came from stress. Very sad because they have so much personality.