Zebra Danio's

[swiftbold]

I have had 3 of my Zebra's die within the last week. They just seem to get sickly all of the sudden. I also have 4 cory's and a pleco in a 29 gallon tank. Zero ammonia and zero nitrite. I do weekly water changes of about 15% of the water. Any ideas on what could cause this and why it is only affecting my zebras? Thanks

 

[Sammie7]

How long have you had them? Did they show any signs of sickness before they died? Where they acting normally before you discovered them dead?

 

[swiftbold]

I noticed acting sickly about 4-5 hours before they died. They all died a couple of days apart. They had been perfectly normal up till then. I have had them for about 5 months. I basically watched as they died I did not just discover them dead. This is my first aquarium so I hope i am not doing anything wrong.

 

[Sammie7]

Danios are said to be one of the hardiest fish in the hobby, so I don't know why they died on you like that. How exactly did they act before they died? If you didn't have any ammonia or nitrite and your other fish are doing fine, I don't know what the problem could be.

 

[swiftbold]

They slowed down and then laid on the bottom of the tank till they stopped breathing. I guess I will watch and see what happens next.

 

[Swayde]

Maybe it's just old age. You say you've had them for 5 months...did you cycle with them? I have read that the exposure to the ammonia and nitrites during the cycling phase can shorten their lifespan, which isn't a very big lifespan to begin with.

 

[swiftbold]

I did not cycle with them. I have one left I am going to give him sometime to see how he does before I put more in.

 

[ralpf]

I was just reading that the Zebra's are susceptible to velvet disease, did you notice any of these symptoms:
Fish rub against hard objects. A yellowish-gray film consisting of tiny spots appears on the fish's body. The fish may also show signs of increased respiration and loss of appetite.

 

[swiftbold]

Increased respiration and loss of appitite, but I didn't see any film or spots. I will check our Velvet disease.