Long fin and regular serpae tetras???

I have 4 regular serpae (also known as red minor) tetras that I wan to increase in numbers, now I noticed you can get long fin ones! Will they group together or should I just stuck with my regular serpae tetras? Also will black skirt tetra (long fin) matter also with its same kind (short fin)

 

Yes, they will group together, but I don't think that the long fins are as hardy.....

 

Ok, thank you for your advice

 

I personally would stay away from the long tailed fish.
They will be prone to attack from the regular Serpae who are notorious nippers

 

Ok, thank you