Two sudden deaths recently in a stable tank

[Snoopdog]

Tank over two years old 79 gallon, we recently lost a very mature healthy Six Line Wrasse. Since he was so large my only guess is he died from old age, he was a really large fish. The Six Line had no visual symptoms, seemed fine the day before. Today, days later we just noticed a dead flame tail blenny. The clean up crew is tearing him up at the moment, so nothing visual that I will be able to tell on him. The other fish seem okay, nothing visual but we have noticed they are not eating as well as they normally do. We are on the reef moonshiners so nothing has showed on testing, in fact the last test was our best one yet. No ammonia is showing in the tank. I doubt it would be stray voltage, I have a grounding probe and I think that would had flipped the GFCI on the wall.

As far as recent events, I did remove some sand from the sump but params still seem to be in check. I purchased some empty frag plugs, but I rinsed them for hours in RO/DI water. I purchased a clean up crew from the LFS but I did a drip method for hours and did not use their water when introducing them. My shrimp all seem okay, but I do have a tiny cucumber that is acting strange and just floating a bit on the bottom of the tank.

Another thing I recently did was get a pump and kind of blast the rocks a bit, there was a good bit of the mulm in between palythoa, which I do have a lot of.

 

[Uncle99]

Any potential for mantis shrimp?
Got two of my bottom/rock dwellers after 5 years.
Used all dry rock as well. Very strange.

 

[Max93]

Do you use candles or spray cleaners near your tank?

 

[Snoopdog]

Any potential for mantis shrimp?
Got two of my bottom/rock dwellers after 5 years.
Used all dry rock as well. Very strange.

I mean anything is possible, but no real fish deaths in a year and suddenly two dead in 48 hours.

 

[Snoopdog]

Do you use candles or spray cleaners near your tank?

No, we are pretty aware. I do not even wear cologne because of that fear.

 

[Snoopdog]

Both of the fish that died stay low to the tank, I am really starting to think it is something with me stirring up the mulm and such. I have heard of horror stories on stirring up a stable tank.

 

[BristleWormHater]

The cucumber is still alive, right?
The are basically bombs when they are dying/dead

 

[MnFish1]

I agree with you on the potential of old age for the wrasse. Just so we're clear - nothing at all was added to the tank for how long? Do you happen to have any other tanks? Without a picture, etc - it's really hard to tell what could have happened to the Blennie. I would carefully watch the other fish. Note - you may have caused a temporary chemical imbalance due to moving the sand - especially with sulfur - and some fish are more sensitive than others to this - which may be the problem. For example I recently moved some Koi from outside to inside - having to drain the pond to do so - leaving a little water and a lot of 'Rotten egg smelling debris". Despite the difficulty and time it took to retrieve the fish - 2 of them were nearly 'comatose' when I found them - within 5 minutes in fresh water they were fine. Many fish would have died much sooner. PS I agree about the cucumber being a potential major problem. Are you running activated carbon? Are there any other fish living in the tank?

 

[BristleWormHater]

The sand seems likely, blennies stick near the bottom and as far as I know wrasse will go down there too. They would get the brunt of whatever you stirred up so it makes sense. I'm still suspicious of the cucumber though.

 

[Doctorgori]

This just happens to me also: 3 perfectly good fish: swimming one day/ dead the next …
…just adding sample and following

 

[Snoopdog]

The cucumber is still alive, right?
The are basically bombs when they are dying/dead

Yeah, a yellow cucumber. He is just not moving, like hardly at all. I have never seen one do this. Normally I see them feeding. He is tiny thought, probably only 2 inches and that is not big compared to the size of the tank. I have tons of shrimp in the tank and they are acting fine.

 

[Snoopdog]

I agree with you on the potential of old age for the wrasse. Just so we're clear - nothing at all was added to the tank for how long? Do you happen to have any other tanks? Without a picture, etc - it's really hard to tell what could have happened to the Blennie. I would carefully watch the other fish. Note - you may have caused a temporary chemical imbalance due to moving the sand - especially with sulfur - and some fish are more sensitive than others to this - which may be the problem. For example I recently moved some Koi from outside to inside - having to drain the pond to do so - leaving a little water and a lot of 'Rotten egg smelling debris". Despite the difficulty and time it took to retrieve the fish - 2 of them were nearly 'comatose' when I found them - within 5 minutes in fresh water they were fine. Many fish would have died much sooner. PS I agree about the cucumber being a potential major problem. Are you running activated carbon? Are there any other fish living in the tank?

Other than the clean up crew, nothing added in many months. The last fish added was around 4 months ago, maybe 6 months.

When I removed all that sand from the sump area, there was definitely the familiar rotten egg smell.

So far today all fish seem to be accounted for other than the two dead ones. Current live count, 2 clowns, azure damsel, two goby, red flame hawk, splendid dottyback. They have no marks, no red gills, just not eating readily like they would normally eat, they are also swimming fine. There is carbon in the sump, but not super fresh carbon.

As an abundance of caution I added another bag of rinsed carbon just now. Well no more stirring up sand beds for me.

 

[Uncle99]

I mean anything is possible, but no real fish deaths in a year and suddenly two dead in 48 hours.

Remote, but this is what just happened to me.
After years of no additions, first was the 5 year old gramma. Then about a week later, a 4 year old dottyback. Clearly beaten.

Both kills on bottom dwellers, I thought it was parasite infection.

Must have been very tiny and overtime, was 6” when I found him.

Not hard to catch.

 

[MnFish1]

Yeah, a yellow cucumber. He is just not moving, like hardly at all. I have never seen one do this. Normally I see them feeding. He is tiny thought, probably only 2 inches and that is not big compared to the size of the tank. I have tons of shrimp in the tank and they are acting fine.

I would err on the side of removing it. Sorry to say - I would never put a cucumber into a reef tank with relatively expensive fish, etc.