This thread is stupid.
fishieperson321 I've read the advice and questions posted here in both of your threads, and they are about the worst I've seen. Which is saying something.
The 10 gallon is too small for your goldfish. You've been told that, I believe mvigor made a comment and you took it poorly. I'll say it too. You shouldn't have that fish in that tank.
So now you say you'll get a bigger tank "when it grows". It won't grow. It will become stunted. Stunted fish's organs outgrow their body size and they die a painful, uncomfortable death.
Now you're asking about getting another inappropriate fish for a 10 gallon, a pleco. The pleco is tropical and the goldfish isn't. Plecos will damage goldfish. Plecos can reach 18+ inches.
I've seen this on someone's sig (I believe monkeytoes) "There is no excuse for ignorance, everything you know can now be found on the internet."
Good sentiment. There can be such a thing as a stupid question. Just as there can be stupid answers (see everyhing pran has ever posted).
I realize this is a newbie section, but just by researching information on this site and a few others about species requirements you would have answers to your questions. You're just lazy.
That and so far you've disregarded or discounted most of the good advice posted to you. For that reason, I probably won't read future threads you post.