I don't know if this applies to the larger sized plecos, but after worrying many hours about my albino bristlenose plecos (they max out at about 5 inches) I realized that they hide for weeks sometimes before a growth spurt. I was very worried about one of mine and put him into a 29 gallon tank because I didn't want him to have to compete with his larger growing companion for food. Well, after about 4 weeks he's out and about and his shape is beginning to change and his whiskers are beginning to come in, and he's eating like there's no tomorrow. Yeah!!! I wanted to move him back into the bigger tank this weekend, but the 29 gallon developed ick because of a malfunctioning thermometer, I think. So, I'm treating for that now. Anyhow, that's my story.
Take care,
Mary.
Take care,
Mary.