Guppy bullying pandas

[JayJay]

My fiancee has just started a tank (12 litre, my old one) and she got 2 Fancy guppies (1 female and 1 male). She has been telling me that the female guppy (not the male) has been bullying and fin nipping the pandas and two have died (many through stress, I tested the water and it's fine).

She asked me to ask here (her English is good but she lacks confidence) how at all to stop the bullying or if it will stop in time. She has isolated the offender in a breeding net as a "jail" but I told her she can't do that forever.

I have never had many bullying problems in my tank (except some brawling Rasboras) so I'm not sure what to tell her.

 

[rich311k]

How much cover is in the tank? Wood, plants etc. She may have to replace the aggressor.

 

[gu2high]

The tank is too small and the female guppy maybe hungry. I have both fish and I don't see any problem between them. I do see once that panda was mad and chased platy fry and guppy fry.