pleco age

Common if well cared for, which most aren't. Congrats.
 
your plec looks pretty skinny.
You aren't looking very close, and plecs don't exactley "pose" in a good way, hard to capture girth when they lay there all day, he lives with 2 oscars and a jag , he eats very well.
I would guess his circumference to be about 8"
 
That's what I like to see! Nice belly on that plec, and it's great he's lived to a ripe old age. Here's hoping for another five years.
 
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