My six year old daughter just got 4 bettas- 2 males and 2 females. We divided my 20 gallon tank so the males would be separated. At first one female went into each side of the tank. The next morning we noticed that one of the females fins are being eaten by her male friend. We removed her from tank and put her by herself, but she wouldn't swim or eat or anything. We put her in with the other male and female and everything seemed fine. She hid underneath everything, but would not eat. A day ago I noticed some gravel was moved from where I had last seen her and saw her trying to tunnel back over to where the original male is kept. We decided to put her back in there since I didn't want her to kill herself by getting stuck under the divider. Today I noticed she now has no fins left except her gills. I took her out and put back with the other two. Can you explain why the other fish is eating my female bettas' fins? Is this a mating ritual or is my female a male?