Neon Tetras and Black Phantom Tetras - Tail Biting

Hi
Hoping someone can offer some advice.
We have a new tank - 56l.
We had 6 neon tetras and 3 corys living in there happily for a month and decided to add some black phantom tetras a week ago. The Black phantom tetras are bigger than the neons - maybe twice their size.
It seems that the Black Phantom tetras are terrorizing the neons. One neon has dies (its tail was badly bitten), another has its tail badly bitten and it looking very unwell. The remaining neons are hiding in the corner of the tank behind a plant. The corys don't seem to be bothered.
I had thought they would all be fine together.
Is this normal behaviour?
Anything I can do to stop it?

Thanks for your help.
Gareth

 

How many of the phantoms do you have? They like to be in groups, so if you don't have enough that might explain it.

 

We had 6 neons and then added 6 phantoms
We're down to 4 neons (1 decidedly unwell) and 6 phantoms still

 

From what little I know 6 should be enough. Hopefully someone more knowledgeable will have some insight.

 

I think overall that your 56 litre or 14-ish gal tank is too small to house black phantom tetra and most types of cories.

 

Hi
Hoping someone can offer some advice.
We have a new tank - 56l.
We had 6 neon tetras and 3 corys living in there happily for a month and decided to add some black phantom tetras a week ago. The Black phantom tetras are bigger than the neons - maybe twice their size.
It seems that the Black Phantom tetras are terrorizing the neons. One neon has dies (its tail was badly bitten), another has its tail badly bitten and it looking very unwell. The remaining neons are hiding in the corner of the tank behind a plant. The corys don't seem to be bothered.
I had thought they would all be fine together.
Is this normal behaviour?
Anything I can do to stop it?

Thanks for your help.
Gareth

Just to be clear do you have Black Phantoms or Black Skirt Tetra?
Black phantom's aren't aggressive or known to be nippers Black Skirt on the other hand are. I would recommend neither for a 56 litre but I think you would be ok with Phantoms.