1st Fish I ever bought died today

[Sashaka]

My Snowflake Ocellaris Clownfish died today. She was 11 years old. I know these fish can live longer in captivity if well cared for, so I'm wondering what went wrong. She did seem to be eating less lately, but she was still of good weight and she was still eating and acting normal otherwise, so I wasn't too concerned.

Background: I did a major sand cleaning in the tank yesterday during regular maintenance...no ammonia spike occurred; however, I found the Ocellaris dead the next morning. I matched PH, salinity, temp, and watched ammonia for changes after disturbing the sand bed as I always do. No issues there. Ammonia badge replaced in December. Just bought a new refractometer. It came already calibrated, but I checked it against my old one and it was reading the same, so my guess is there were no issues with salinity level. More specifics below:

It's a 29 gal FOWLR, running for about 10 years (never had an algae, cyano, or fish disease outbreak - even when first setup)
Biological filtration: 4X4 Marine Pure block and a few extra Marine Pure balls
Mechanical filtration: HOB Filter filled with floss and a small amount of rinsed fresh carbon
Small pellet reactor to control Nitrates
HOB Skimmer
Cheap LED lighting-not adequate for corals

0 Ammonia
3 Nitrates
35 ppt salinity
76 temperature
8.1 PH (a little low, but not a big concern in a FOWLR)
I generally don't check for anything else in this tank because it does not house corals.

Tank stocking list
1 Yellow clown goby
1 Ruby Red Dragonet
1 Tailspot blenny
1 Royal Gramma Basslet
1 Yellow Priolepis goby
1 Fire shrimp
1 Red Banded Snapping Shrimp
1 Halloween Hermit Crab
Assorted snails

Diet
Frozen food mix (my own concoction of about 10 different items with the two largest ingredients being mysis and Rod's Food for carnivores) in the morning-vitamin soaked for 15 minutes
A small amount of flake and pellet mixed with frozen in the evening
Nori once a week

Any idea what caused the clown to pass?

 

[Old Fritz]

Lifespans (especially for designer clowns) can be all over the place. See the thing is age is just "if you don't reach x amount of years something was wrong with your tank" its just like how not all of us live to 90 years of age. Some of us will only reach 60 some will live into their hundreds. Same thing with fish.

 

[ScottR]

Could have been nitrogen built up in the sand. @Mastiffsrule had a similar thing happen to one of his fish after stirring up the sand.

 

[Paul B]

Tough question. "Normal" clowns live over 30 years but yours is not normal and whatever they do to make it into a designer clown may also affect it's longevity. But I doubt anyone has any idea.

I think he lived a good life and that may just be her life span.

How to Tell if a Marine Fish Is Dying of Old Age

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[Radman73]

Condolences. My clowns are coming up on 11 as well and were also my first fish, so not looking forward to that day either. 11 years for any fish should probably be considered a success in a home aquarium, so in my opinion, you did well.

 

[Peace River]

I am sorry for your loss. It sounds like you have done well for many years and did a good job caring for you fish.

 

[NJDragonet]

It was probably the sand when designer clowns get a certain age in their tank they get VERY sensitive to anything that changes in the tank I had a snowflake that lasted for 15 years then I clean up the sand move the rocks around next morning I find him dead

 

[Ruben's Reef]

Sorry for your loss. I feel bad when one of my fish die but having a fish for 11 years its means part of the family so the feeling is worse.

 

[Sashaka]

Thank you for the kind words, @Old Fritz , @Paul B , @Radman73 , @Peace River , and @spyder813 .
While I have made some major mistakes in this hobby over the years, it's comforting to latch onto some hope that this was not one of them. Aside from the last week or so, the clown was such a spunky little fish, bit me every time I stuck my hands in the tank! I will miss her spirit. The article you shared, Paul, about the behaviors of fish passing from old age did seem to bare similarities to my clown's behaviors the last week, except for the bullying during end stage. She was top dog in that tank. There really were no other fish in the tank capable of bullying her, and she bore no bullying injury marks of any kind. She looked to have lost a little weight, that was all. I could have opened her up and put her under a microscope, but I didn't have the heart, and I'm not sure I could have identified what happened anyway as I'm not in the medical or scientific fields, so my diagnostic abilities are quite limited. I can't ever be sure what she died of, but imagining she passed of old age is definitely comforting.

@ScottR and @Njcoral101: I did a major sand cleaning, scooping out the sand and rinsing it until it was clean. I don't need the sand for biological filtration with the Marine Pure in the tank, so every few years I remove all the sand, clean it, and return it to the tank in an attempt to keep it from becoming a nitrate factory. The sand was pretty dirty this time and clouded up the tank. It was definitely overdue for a thorough cleaning. I picked out the critters from the sand before rinsing, but as always, I missed a few spaghetti worms and snails. They survived the rinsing just fine, so I thought all was well until I found the clown dead the next morning. I didn't even consider a nitrogen build up, though that sounds logical. I did do about a 50% water change to clean up the water after I rinsed the sand clean, but scooping the sand from the tank could have been the problem. I've siphoned it out in the past. Next time I do a major sand cleaning on this tank, I will be sure to siphon, not scoop the sand out to try to reduce an overload of nitrogen into the tank and I think I'll only do half the tank at a time, wait a week or so and then do the other half. If a large nitrogen release was the problem, dividing the cleaning task over a period of days should help. Thank you for the tip. I wish I would have thought of it before cleaning the tank.