I have tried to feed my goldfish romaine lettuce once and a while, and it ends up floating there for a day. I take it out then, but they just leave it be. They don't even care about it, they don't go up to the top for it. Am I doing something wrong?

How do you prepare it? Do you blanch it? You could try one of those veggie clips that suction to the aquarium wall. That way the lettuce is in a vertical position and stays in one place, so the goldies aren't having to chase it with the current.

My fish also won't touch lettuce (romains or leaf)....I've even riped it up in tiny mouth-size pieces, which they will just spit out. I think some fish just tend to be picky eaters...and mine especially don't like a lot of the things I've tried feeding them (at least 2 of the 3 have hated lettuce, brocolli, carrots, strawberries, pear, orange, banana, melon, and now they won't even eat cucumber!).
I would recommend trying to blanche the lettuce (cook it for a few mins), but if they still won't eat it, then they just might not like it.

I had a plecos gobble up the peas I put in, thank goodness. The gold fish looked at me like I'd lost my mind! Same thing with orange slices and I've seen them fed at the LFS..again all I did was mess up my tank so I had to do a huge water change. Plecos didn't want oranges. I know many don't keep a plecos with their gold fish....I'm doing so far so good.......peaceful and the plecos is small, not bossing around the gold fish. Now if the PEAS don't kill the plecos!