Fish Dead - But I still have questions.

[Bethany97]

For the past 3-4 days one of my two clownfish has been MIA. I assume it had gotten caught in a crevice and was having trouble getting out. I never found a carcass in the filter, so I assume it is still alive in my tank (???).
Anyway, the second clownfish has been eating, active, and healthy looking throughout all of this.

I get home today and discover the clownfish I thought was healthy stuck to the filter intake. I quickly quarantined him and started some rapid cure meds on him, but he looked too far gone at this point. He died an hour later. The other clownfish has still not been spotted and now I think it has probably died as well.

My question is... What happened?

The clown showed no white spots such as ich or fin rot. I don't see signs of injury, etc. I'm at a loss. I've had this pair of clowns for about 6 months.
The fish was eating up until the day it died. Tank mates include a firefish goby and scooter blenny, both of which I've never had problems with as far as fighting goes.

Water parameters are fine. Nitrates are low, but nitrites are very high (80ppm) from the recent death, I suspect? I'm doing a 60% WC after posting this.

Do I need to take the remaining fish out and treat them for parasites or something?

 

[pandagobyguy]

Nitrite is super toxic from what i understand. Id WC to reduce... idk what happened but what kind of filter did it get stuck to?

 

[Smo]

Nitrite is more toxic to freshwater fish than saltwater, although 80 ppm is a bit high. Are you sure you did not have an ammonia spike? What size tank? The first clown decomposing could have fouled the water.
Any recent additions to the tank? Any other fish showing symptoms of rapid breathing, sensitivity to light, flashing, scratching, swimming into a power head?

 

[Bethany97]

Nitrite is super toxic from what i understand. Id WC to reduce... idk what happened but what kind of filter did it get stuck to?

It was a HOB filter I've used since I got them. A healthy clownfish should have had no trouble getting stuck.

Nitrite is more toxic to freshwater fish than saltwater, although 80 ppm is a bit high. Are you sure you did not have an ammonia spike? What size tank? The first clown decomposing could have fouled the water.
Any recent additions to the tank? Any other fish showing symptoms of rapid breathing, sensitivity to light, flashing, scratching, swimming into a power head?

An ammonia spike isn't impossible, I have been known to overfeed once in a while. They're in a 28 gallon. These clownfish are the most recent addition. The only other thing I've noticed is that my scooter blenny has been rather pale, but he's known to change colors in the past.

 

[pandagobyguy]

Nitrite is more toxic to freshwater fish than saltwater, although 80 ppm is a bit high. Are you sure you did not have an ammonia spike? What size tank? The first clown decomposing could have fouled the water.
Any recent additions to the tank? Any other fish showing symptoms of rapid breathing, sensitivity to light, flashing, scratching, swimming into a power head?

Thats makes total sense. I was refrencing a book about planted tanks when i mentioned that...

 

[reef lover]

Check your ammonia levels with nitrite that high....

 

[Dilan Patel]

With Nitrite being that high an level of that is toxic to marine fish. Marine fish are more tolerant of Nitrate. Just wondering how long has the tank been up and running as well as did it fully cycle yet. So the way the tank cycles is everything starts out as ammonia which is deadly than bacteria change it to Nitrite which is still deadly at readable amounts but overtime(cycle process) this Nitrite is consumed by bacteria that is grown which helps convert to less deadly nitrate. If you add too many fish at once or one dies the bacteria may not be able to handle the new biolad leading to an imbalance which could have caused your fish to die.

 

[Smo]

How long ago were the clowns introduced? It’s possible they carried some disease into your tank that may now have infected all your fish. Lots of nasty stuff in the supply chain now that can be suppressed with low doses of copper in the LFS’s tanks but when introduced in your tank it runs wild.
I am assuming you have not quarantined and prophylactically treated your new additions.