I am hoping for some advice regarding my fish....Ater acting strange for a few days one of my zebra danio's died. The only symptom I could see was thin, white long stringy poo (sorry tmi..) It was swimming in a strange way and kind of dive bombing the bottom of the tank. Anyway today ive just noticed that one of my black mollies looks like she is dying, hardly moving and also has this long stringy white stuff hanging out... Any idea's as to what this is ?? and how to treat? I have 11 other fish in the tank, is it likely to spread as it it seems to of already? Thanks for any help.