Disease in one of my tanks is killing all my fish

[mayreee]

I don't know much about this so I am not sure anyone can help me. I got 4 new neon tetras and 4 corys. I put them in my 15 gallon along with one black molly and 2 neons I already had. In 2 days 4 neons have died. I saw no signs of disease on them except the last one that died yesterday. It had cotton like stuff on its head. Then today I wake up and one of the corys is dead. It had some streaks that look like blood on it and it tail was missing. I don't know if some of the others tried to eat it or what. I will be real upset if all my fish die so I need to find out what I can do to stop this. Thanks!

Ammonia 0
Nitrite 0
Nitrate 10

 

[TankGirl]

Possibly columnaris, hard to tell. This is a good reason to quarrantine new fish, so they can be deemed healthy before adding them with the fish you already have.

Here is one of Menagerie's handy links for illness ID:
http://www.aquatronicsonline.com/hobbyist/hobbyist3.htm

 

[mayreee]

One more cory just died That is 6 fish in 4 days in that tank only. None of them even had any sign of disease before they die. After one of the corys died, when I discovered it in the morning it had sign of Septicemia. Is that contageous? I know they all are going to die if I don't do something quick

 

[Maillis]

The red streaking does sound like septicemia; an internal bacterial infection that affects the blood. It usually isn't contagious unless a fish eats another infected fish. I'd use Kanamycin (Kanacyn) to treat bacterial infections.

 

[Menagerie]

Hope that it is the bacterial infection and not the viral infection. Definately begin treating with Kanamycin. It can be added to the water, but is more effective if added to the food and fed to the fish.

 

[julieanne]

It had cotton like stuff on its head.

id treat it with something salt maybe 1 tsp per 5 gallons or another antibiotic cotton patches is cottonwool disease and it needs treatment whatever you do do it fast before you lose your whole tank