In defence of roofer32 i have seen flatfish photographed and incorrectly identified on this site ive also heard many small flatfish given the name "dab" especially when caught far up estuaries that are clearly flounders and several spotted flounders called plaice. Recently ive had reddy /orange spotted flounders and yellow/red spotted big dabs both of thes could easily be misidentified .The easiest way ive used to explain differences is that flounders have solid white bellies ,plaice are slightly more oval but you can see through the whiteness on there belly they are slightly opaque,dabs when stroked on there back from tail to head have a roughness whereas the flounder and plaice are smooth either way .Please feel free to add to this but its worked for me for 33 years