Fish id question

[Great Lakes]

I once purchased a couple of fish at the local Wal-mart. The kid working didn't know what they were, and I have never seen them again anywhere. They were about 2 to 3 cm ROUND. Looked like a little Manta ray. They liked to sit on the bottom, or on the glass. They were grayish on top and looked kind of fleshy on the bottom. I believe they eventually feel prey to something larger than them. But I keep my eyes open for them cause next time I will give them their own tank.

 

[pete]

Were they like a cross between a Pleco and a Ray?

If so they might of been the Hong kong Pleco's discussed in the Catfish section

 

[Great Lakes]

I think they were fry of some sort, but never got big enough to develop any noticeable characteristics. Someone once posed that they were flounders.