Sudden death of 3 fish - please help!

[philbowen]

I have a 240 litre jewel aquarium with 2 external filters, 2 powerheads, skimmer, live rock & live sand was inhabited by

Pair of maroon clownfish
Clarke's clownfish
Regal Tang
Cardinal
dottyback
yellow wrasse
chromis
foxface rabbitfish
yellow tang
fairy wrasse

All living happily together no signs of disease and feeding well.

Suddenly today the rabbitfish, yellow tang & fairy wrasse were all foun d dead at the bottom of the tank all very close to each other. PH, Nitrates, Temp & salinity are all ok. The Carke's was looking unweel but now seems to have recovered.

I know its a long shot, but any ideas? Could the rabbitfish have posioned the other 2 and itself?

 

[Kurt_Nelson]

How long has the tank been set up? Any detectable ammonia or nitrites?

 

[philbowen]

This morning the pink dottyback is dead, it appeared fine last night. It looks like none of the fish are now feeding.

The tank has been set up 6 months. The nitrate level was 20-40 using an API test kit. The nitrite is 0.1 - 0.2 using a red sea test kit. I do not have an ammonia test kit. I am going to take a water sample for testing to my local fish store.

I should add that I also have in the tank 2 long spined urchins & 2 cleaner shrimps plus 2 pieces of coral all of which appear fine.

 

[Ziggy953]

That is an awful lot of fish in a 6 month old tank. Since you are showing NitrItes I would venture to guess you have ammonia present as well. I would suggest some immediate PWCs. A minimum of 20% and I would do a few of them over the course of the next several days. While you are getting your water tested pick up an ammonia kit so you can test yourself.

I think you added too many fish too quickly and that could be the reason behind the sudden deaths. Doing the PWCs (partial water changes) will help reduce any ammonia, nitrites and nitrates that are present in your system.

How often do you change/clean your filter media? What kind of filter media are you using?

 

[melosu58]

That is an awful lot of fish in a 6 month old tank.

I agree with Allen that is alot of fish in that size tank. I`ll be willing to bet that if you did check your ammonia out that it would be high. Hate to be the bearer of bad news but that`s one big bioload for that size tank.

 

[Kurt_Nelson]

I agree with Allen that is alot of fish in that size tank. I`ll be willing to bet that if you did check your ammonia out that it would be high. Hate to be the bearer of bad news but that`s one big bioload for that size tank.

That's pretty much where I was going with my questions too...

 

[austinsdad]

Also, look at the pectoral fins on the fish still living. Any teeny weeny white dots there. The stress of the ammonia, nitrate, nitrite, and that overcrowding in such a young tank can cause enuf stress to start a marine velvet outbreak. It kills very fast.