Penguin Tetra Nipping A Black Phantom Tetra To Death

[abyssangel]

Hi,

I have a 10 gallon tank with 6 Black phantom tetras, and 2 penguin tetras. I got them 3 days ago. The problem is that one of the small penguin tetra keeps nipping on one of the black phantom. He almost nipped his tail fin completely, and I am afraid that he kills him. He keeps following him in the tank to nip his fins off.

I did my tests this morning and everything seems fine: PH: 7.2, nitrite: 0, nitrate: 0, temp: 25C.

I noticed that the black phantom that is losing his tail has one cloudy-eye. I did not notice if it appeared before he starts getting bullied by the other one or after.

For now I am just really scared that he dies, and mostly that the small penguin tetra starts picking on other fish next.
I do not have a car so I can't really bring him back to the pet store, at least not before next week-end.

What should I do?

 

[fluttermoth]

I'm afraid there's not much you can do, except separate the culprit. Many tetras are nippy if in too small a group (at least six individuals, really).

The cloudy eye could be injury, or it could be down to poor water; I know you've tested it, but you don't seem to have tested for ammonia, which is the biggest problem in new tanks. Are you using test strips, as I've noticed they often don't test ammonia levels?

Was your tank cycled?

 

[abyssangel]

Sorry, I forgot to write ammonia level. It was at 0.3, which was in the green zone of the chart that I refer to.(I am using the Nutrafin test kit)

I did a partial water change this afternoon.
I also noticed that all my other fish are fine.

The poor black phantom one is just floating around in the plants, unable to swim...I'm afraid he doesn't have much time left. I keep watching the nippy one's behavior and will take him out of the tank if I see him doing this with any other fish. Since I do not have another tank though, I am afraid I will have to sacrifice it.

EDIT:
Well, it seems to be over. I had lost the fish at a certain point, and spent a good part of the day looking for it everywhere.
Couldn't find it until I realized: I found a side fin hanging in the plants(a whole one), and there is something that appears to be an eye or a piece of skin in the bottom of the tank.
I guess he died and got eaten by the other fish.

The little one who was picking on him is now fine and does not bother other fish. Back to normal in my tank.

And R.I.P. the fish who got bullied by a much smaller one