clown dead....possible poisoning?

[Skeptic9962]

today i noticed when i came home that my clarki clown was sitting close to the bottom of the tank upside down, he was still breathing and fighting but couldnt swim eventually he died...my question is ive had mysterious deaths in this tank over and over again...within a matter of an hour or so they will be swimming perfectly fine and eating fine and then all of a sudden be on the ground dieing...its happened to 2 fish so far within 6 months... params. in tank are good granted the nitrate needs to come down a bit but that isnt the cause...its only 20...this is a soft coral tank so what im wondering is could a coral sting/poison a fish to the point of it quickly dieing....

both the fish didnt have any scrapes or nips on their fins and only other fish in this tank is a yellow mimic tang and a small sixline wrasse...

any input is wanted

thanks

 

[russellaqua]

20 is definitely the upper limit of nitrates. Have the fish died shortly after introduction or have they survived for a while before dying? If it's very shortly after introduction I'd say that the acclimation to their new tank was too fast, but if they survive for a while it may be that they were cyanide caught fish. If a fish receives a low dose of cyanide during capture they can survive a couple months before eventually succumbing to the poison. Do you know if the clarkii was wild-caught or captive-bred? Both are on the market so it's hard to know what the problem might be without that info.

 

[Skeptic9962]

both of the fish had been in the tank for atleast 6 months prior to death....i know that the clarkii before was a clients of BRA and had been in there tank for along time also not sure on length of time in others tank though....

20 is definitely the upper limit of nitrates. Have the fish died shortly after introduction or have they survived for a while before dying? If it's very shortly after introduction I'd say that the acclimation to their new tank was too fast, but if they survive for a while it may be that they were cyanide caught fish. If a fish receives a low dose of cyanide during capture they can survive a couple months before eventually succumbing to the poison. Do you know if the clarkii was wild-caught or captive-bred? Both are on the market so it's hard to know what the problem might be without that info.

 

[russellaqua]

Hmm... might be the nitrates. The fish in the tank may have had time to slowly adjust to the elevated levels. You might try slowly bringing them down (so as to not shock the fish you have in the tank now) and then try another clown. That's the only thing I can think of. It's strange to see a fish go so long before dying. Usually it's relatively shortly after introduction to the tank. I would think any parasites those fish might have had would have killed them sooner.