Sick clownfish, please help!

[Samc]

Okay gang,

 

My 20 year old clownfish (yes, I have a 20 year old clownfish, my family and I have had him since he was 7, and he's a tough SOB). Currently he is living solo in a 29g tank, and has been for the last half decade or so. Saturday a week prior he started acting strange, hiding behind the overflow box and not coming out to eat. Upon close inspection, there are no visible signs of destress. A week later, he still hasn't eaten. Things done since his behavior change:

 

1) immediately added a heater to the tank and a thermometer; thinking the tank temp dropped and precipitated this (in my experience, temperature changes are the root cause of most fish problems). Tank temp is a steady 78-80 deg F.

 

2) Performed a mid week 5 gallon water change, along with changing activated carbon and adding phosban. Behavior improved but still no eating

 

3) feeding frozen brine shrimp with garlic to no avail, still haven't seen him eat for a week!

 

Tank stats:

Temp: 78-80

PH: 8.15

Salinity: 1.025

 

I don't test for ammonia, nitrates or nitrites. Haven't in almost a decade-the water change would have knocked any trace nitrates out and with a live rock and sand bed, plus protein slimmer capable of supporting 5 times this bio load I'm just not worried. Everything else in the tank looks healthy, cleaner snails moving around,

Coralline algae growth decent, rocks look good. Don't have coral in the tank at present and haven't added any new inhabitants in several years.

 

Any thoughts on what this could be? Running theory here is old age but would love some expert advice!

[RIP Sebastian]

Sounds like old age to me.

[Clown79]

Try feeding mysis.

 

Is there any runny white poop?

 

Could be just age

[Samc]

No runny white poop.

 

He's eating a little bit of food with garlic. Still won't come out and swim around. Agree age is the common denominator.