Baby gubbies

[Sink or Swim]

I have about 20 - 30 baby gubbies at 4 weeks old. I would assume they are a mixture of both sexes but they all look females. Is this possible? how can the males be idendified?

 

[lilfishie]

mine are all female to start with but as they get older you will be able to tell(sometimes males are smaller than the females)