My new fish are dieing

[Bryan]

I wasn't getting any help in Tropical Fish Emergencies so I thought I'd try here.

I've had 4 fish die in the last 3 days. 1 zebra danio, then 3 pencile fish. It looks like the pooped out a bloody bowel. Right now there is one zebra that is going to die, it looks like it's guts are all bloody. How do I explain this, the area around it's intestines is red and it don't eat and jst sits still. I took a sample of my water to the LFS and all levels were good.
The bad thing i did was I bought 12 zebra danios from wallmart and I think they have some disease, but 10 of them look really healthy, for now.
The LFS didn't have marycine II so they gave me this

Will this work? or is this just for external problem?

Can anyone help?

 

[turbotiber]

Have you separated your "healthy" fish from the ones that look sick? If they're all still together, maybe that's why other sick got fish as well.

Bloody guts you say... soudns like an internal problem

 

[sylvia]

Most probably your problem is some kind of internal parasite. Melafix can help with many things from what I've heard but I've never used it for this kind of thing myself and cannot say whether it will help in this instance or not. It says anti-bacterial so you'll have to treat in a seperate tank or risk a re-cycle though it does say it won't harm your biological filter. Personaly, I wouldn't risk it as it may have a little effect though maybe not very extensive. I think it's worth a try but I don't think it'll help with a parasite (if that is realy what you have)...