Black ich in 75 gallon, all fish died. help !

[edelarosax729]

Hello,

I've had a saltwater tank for about 5 months now. We let the tank cycle checked that the water levels were okay before we introduced fish. We had a naso tang, a yellow tang, a sailfin tang, a clown fish and 2 other which i dont recall their name. Suddenly, my naso tang was having black dots which then made him very weak and eventually killed it. The same thing happened to all the fish in the tank. Eventually my entire tank is wiped out from fish. I am scared to add any fish because clearly whatever the tank has going on it's going to kill anything I introduce to it.

Has anyone ever experienced any of this. Please help, i miss looking at my tank with fish swimming around.

[m0nkie]

you need to fallow your tank. I recommend full 3 months before adding new fish.

Or you can start over.

QT your new fish..

3 tangs in 75 will cause too much stress. Try smaller fishes.

[ThRoewer]

It would be helpful to get more info on the tank, the fish and a detailed timeline of events.

If it was black ich you are dealing with a turbellarian worm infection. The medication I would try first in such a case would be Praziquantel (PraziPro).
Fish - especially tangs - from Hawai'i are quite often infected with this parasite.

The 3 months fallow are for Cryptocaryon - not a particularly bad idea, but not necessary helpful in eradicating black ich as the worms can live for more than 3 months without fish: Black Spot or Tang Disease (http://saltaquarium.about.com/cs/compldiagnodisease/a/aa041701.htm)
Here is a scientific paper about it:
Interrelationships of a Parasitic Turbellarian, (Paravortex sp.) (Graffillidae, Rhabdocoela) and its Marine Fish Hosts (https://www.jstage.jst.go.jp/article/jsfp1966/21/2/21_2_65/_pdf)

A 2 months quarantine period for each new fish should be observed to prevent future introduction of diseases and tank wipeouts.