Fish suddenly dying but parameters seem fine

[gentlefish]

Flukes are parasites on the fish body that are translucent, invisible. If a fish or a recent deceased fish gets immersed in freshwater, they turn pale white and fall off. There is a good YouTube video about it. While it needs to be done correctly as it can be stressful to live fish, it can also be done as a postmortem. And yes, it’s just another way to loose fish. Bit more subtle and prolonged than your typical ick/velvet. Jay Hemdal in the disease forum is an absolute specialist about those.

 

[Algae_Farmer]

Flukes are parasites on the fish body that are translucent, invisible. If a fish or a recent deceased fish gets immersed in freshwater, they turn pale white and fall off. There is a good YouTube video about it. While it needs to be done correctly as it can be stressful to live fish, it can also be done as a postmortem. And yes, it’s just another way to loose fish. Bit more subtle and prolonged than your typical ick/velvet. Jay Hemdal in the disease forum is an absolute specialist about those.

Good to know, I'll try that. Thanks!

 

[Algae_Farmer]

That cracked me up "Lately".. haha ;Playful Just how many times HAVE you found odd things in the tank?

Ha! Well, not too many times. There was this issue with mysterious pasty goo a while back.
Never did figure it out, but the pasty chunks seemed like a calcium precipitate. Once in a while a small flake of soil from frozen food, Etc but I've always gotten those out...

 

[Algae_Farmer]

I've been trying to remember any changes lately. About a week ago I pulled some GHA from rocks, and plucked a few Kenya trees. Since then the GHA has definately receded quite a bit on its own, which is surprising to me.

Do Kenya trees release some kind of toxin when picked off rock?

It's possible I kicked a green polyp when pulling GHA, but I'm usually pretty careful so didn't think so. Could that make it release palytoxin and kill fish?

I did just spot an Astrea snail that had gone completely white. Seemed odd until I realized it's now a hermit crab, so maybe it found the shell under rocks which would explain the lack of coloring?

I also stirred the gravel up a bit last week when cleaning, not very much, just enough to knock the cyano loose. Certainly shouldn't have been enough to start a mini cycle. That's about all I recall for recent changes...

 

[Jay Hemdal]

Good questions.
No noticeable damage on fish (except decay), no fungus, holes or strange marks/spots.
I have a ground rod going to electrical ground.

Household chemicals are a possibility as DT is open top, also possible kid did toss something in, although I haven't found anything odd in there lately...

Just to clarify - stray voltage does NOT harm fish, as they are not grounded. Most, if not all external sources of poisonings would harm invertebrates along with fish, often the invertebrates, being more sensitive to water quality issues, will die from poison before the fish. Since you are just losing fish, it is most likely a disease process. You mentioned the change in food as being a possibility. The only thing I can tell you about that is that it could be, if the food was allowed to completely thaw out during transport, that it could have gone rancid, and then if it was refrozen, you could be feeding out bad food and not be aware. However, that is very rare, and usually, when that happens the food is still edible, it just loses nutrients (which wouldn't kill the fish outright).

jay

 

[Algae_Farmer]

Just to clarify - stray voltage does NOT harm fish, as they are not grounded. Most, if not all external sources of poisonings would harm invertebrates along with fish, often the invertebrates, being more sensitive to water quality issues, will die from poison before the fish. Since you are just losing fish, it is most likely a disease process. You mentioned the change in food as being a possibility. The only thing I can tell you about that is that it could be, if the food was allowed to completely thaw out during transport, that it could have gone rancid, and then if it was refrozen, you could be feeding out bad food and not be aware. However, that is very rare, and usually, when that happens the food is still edible, it just loses nutrients (which wouldn't kill the fish outright).

jay

Interesting, thanks @Jay Hemdal! Assuming it is a disease, where does one start on diagnosing if there's no obvious symptoms? Is there a lab or something I can send a dead frozen fish to? Like a fish autopsy?

 

[Jay Hemdal]

Interesting, thanks @Jay Hemdal! Assuming it is a disease, where does one start on diagnosing if there's no obvious symptoms? Is there a lab or something I can send a dead frozen fish to? Like a fish autopsy?

There are some vet labs that work on expensive koi, but the tissues can't be frozen.

Make sure that your refractometer is properly calibrated. If the fish loss ceases after the food change, well, I guess I would conclude that was an issue.

Jay

 

[Algae_Farmer]

Update -
OK, so I came home today and noticed that now the corals are a bit distressed after all. Zoas and green polyps are partially retracted, Kenya trees (I know, but my wife likes them...) are shrunk like they just got out of a cold swimming pool, clove polyps are looking scrawny, etc.

Odd that they didn't show symptoms until after so many fish died? Anyway, I haven't lost anymore fish (still have one Bangaii, gold midas blenny and 2 percula clowns).
I have now:
- sent off ICP and N-DOC tests
- did 15% water change (another coming up)
- added cuprisorb
- stopped using the new food
- inspected for anything out of ordinary (nothing yet)

 

[Algae_Farmer]

Iodine. Turns out it was iodine off the charts. Icp test showed 907 ug/L (30-90 is typical range). I did occasionally dose iodine manually, but it was minimal, infrequent and doesn't seem likely to have thrown it that far off as a stand alone source. In lieu of some other random source I suspect the 4 year old may have "helped daddy" as she likes to play near my lab area in the basement.

No more fish have died since I started doing weekly water changes of about 15%. The elevated iodine did seem to be an impressive cure for GHA, and the little bit of cyano I had, but it didn't set the bubble algae back at all, in fact it seemed to really like it.
Thanks again to all the folks who provided positive advice and insights!

 

[theocorals537]

Thanks! Good ideas, will try...

We’re the fish quarantined? I never took it seriously until a single fish killed all of my favorite large angelfish that I’ve had for 7 years. All of my fish died in under a week, ones that I have watched grow from a baby. The most important thing I tell reefers is invest in a qt tank, your fish will be much healthier , and you will have much more peace at mind

 

[zalick]

When you were dosing iodine were you also testing?

I hope this was issue and it’s solved.

in the mid 90s when I started my first reef tank I squirted iodine in the tank once a week or so. Never tested anything and never had an issue.

I’m skeptical that iodine is your issue. Here is a post from Randy in a different thread about how fast it breaks down.

What form are you dosing? Iodine comes in a variety of different forms with potentially different toxicity. Iodide, iodate, iodine (I2), organic forms, etc.

I'm not personally convinced most tanks benefit, but if you think yours dose, there's no reason to not use reasonable amounts. It depletes fairly fast because algae (macro and micro) take it up.

 

[Algae_Farmer]

When you were dosing iodine were you also testing?

I hope this was issue and it’s solved.

in the mid 90s when I started my first reef tank I squirted iodine in the tank once a week or so. Never tested anything and never had an issue.

I’m skeptical that iodine is your issue. Here is a post from Randy in a different thread about how fast it breaks down.

Interesting, thanks for the RH-F link. I'll check the form as I recently did change brands (to brightwell). No, I wasn't testing, I know that's bad but dosed it so infrequently I didn't think it'd be an issue. (also didn't want to spend the $ on yet another test kit). Yes, I've learned that lesson. :/