I came into the office this morning...fed the fish, and noticed one of my female zebra danios is missing its tail, from the dorsal fin-back. This is my 5g tank, which is stocked with 4 ZD's(1m 3f) and a small CAE. She doesn't look stressed...I spend most of my day with these fish, considering theyre right next to my monitor at work...and they never fight. The CAE has nothing to do with them, and vice versa. The females look swollen, but I don't know if any are laying...I noticed that 1 male and his "chosen" female are very protective of the live plant I have...but I dont see any eggs.