Thanks Eric. Funny to see a yellow lightbulb swimming in the tank

Here is a quick and dirty picture of my yellow oto
https://photos.app.goo.gl/dQiz28kfcrM1sNc67

Thank you Jeanne and Eric.
I will try to catch him with my phone, but it looks just like in de link: a yellow head and part of his upper body also. Can it be old age? I had him/her for about 5 years now and I got it fully grown.

My Otocinclus Vittatus recently got a yellow head and part of his body also.
He/she looks fine, eats well, is active.
It looks almost like this: https://www.aquariumglaser.de/en/fish-archives/otocinclus_vestitus_paraguay_en/

I couldn't find a clear answer online so I post it here to you experts ...