So your answer is just to return everything. No my Pleco is just fine I have a 60 Gallon Tank and yes he is about 7 inches long. He is very docile, as he moves around the tank, but he doesnt move around alot, he is quite lazy from the day we got him. The woman I bought him from had a 75 gallon and said the same thing, he has always been lazy, so I bought a small albino Plecco also. So the tank actually gets clean. Next The tetras. I bought 4 at first because that is what they said, two ganged up picked on the other two till they died. Now they are happy as a lark together, side by side, and don't bother anyone else, So no I wont be putting any more in.-more on that in a second. My Upside down catfish is the same, we had two, and they stayed apart from each other. And we lost the second one to a case of Ick, when I brought in yet two more tetras to get more for them to be a "clan" again. So I wiped out half my tank trying for that, plus the two were ganging up on the new two the whole time. So they are fine in twos. I believe it is a corey as the person told me in the store, no I have not been able to find a picture of him. I call him Arnold (for the actor) because his head and everything are so muscled looking and he is a bottom feeder and cleanes to gravel, all over the tank all by his lonesome.
So if my attachments load, you can see the neon fish, Arnold, , my orange and blue/silver Fantail,- (Ricky and Lucy) also the yellow with black spots one.