A Stripped Raphael I use to have....Only time I ever saw him was when I took everything out of the tank for a thorough vacuuming. A shame, because they are so cool looking.
Now, I have an Ornate Bichir who I wish I saw a lot more, and a Clown Pleco I never see.
I have a pleco of some various nature in my 150G. I see him maybe once or twice a month...Ive had this fish(purchased for a common) for over 2 years and it has been the same size since...roughly 5". Hes always got a little pot belly so...I assume it eats despite the fact Ive never seen it happen
I rarely ever see my black khuli loaches, sometimes i don't see them for weeks, then when some stormy or really rainy weather comes along the khuli loaches go crazy in the tank for about a day and then go back into hiding.