Disappearing Corydoras

[SheppyFish]

My three Golden eared corydoras, who behaved normally (if a little nervously) since I bought them, disappeared! Small tank only Neons and Zebras in with them. I have been seriously looking for them for about a week now and dreaming up unlikely theories for what could have happened. None convincing! Finally got time to take all the scenery out of the tank today hoping to find some evidence of their demise and there they were under a piece of bog wood that is a bit concave where it meets the gravel. They were very dark in colour which sort of makes sense as they seem to have decided to shun the world of daylight.
They looked perfectly healthy, and having given the tank a bit of a clean, I put everything back as it was and they have now disappeared again.
Anyone know what's going on here?

 

[librarygirl]

Not sure exactly, I'm still trying to figure out my Pandas lol. I think they prefer dimmer lighting so if you have strong lights that are on a lot, that could be why. Also Corys in general are nocturnal so they may be more active at night when you don't see them. How long have you had them and what size tank are they in? Is the tank cycled? They do prefer larger numbers if your tank can hold them. I have 7 Pandas and 3-4 are very active even with the lights on, the others tend to chill under plants, not sure why.

 

[SheppyFish]

Had them about 4 months. Tank a cube 30cms. They only disappeared recently. I'm often up quite late but they don't seem to come out at all now! It's really a bit weird cause nothing has really changed in the tank, except I bought 4 more Zebra Danios (went from 2 to 6). Maybe that upset them a bit?

 

[librarygirl]

Hm, how many gallons is that? It sounds rather small which could be the issue.