Not so sure about seriously fish but fishbase is definitely quoting a size for meridionales.
Josh is suggesting that the 20 inch(505mm) has also been reclassified as meriodontales(which is what seriously fish quotes). It seems like this reclassification is a recent event and the info on those "care sheets" all over the net, not just seriouslyfish, is outdated but not incorrect as meriodontales is a sub species of senegalus...
Ok lets take this slow. Where were you able to correct the misinformation?
Again using your care sheets i could decide that i could never house a sen, but run out and purchase an ansorgii and end up with a monster poly living in horrible conditions.
Did you ever see the movie ragging bull ?