This is the exactly what I posted when you brought this up in the other thread:
"Commonly 7" to 10" but it's not unusual for them to reach larger. Frequently up to 16". The IGFA record is almost 20" and 3 lbs. So the question becomes do you assume you'll have a small fish that may actually be stunted because you kept it in a too small tank or do you try to give the fish it's best chance to grow as much as possible by providing larger quarters. I vote for the latter and advise against keeping this species in a 55 gallon tank."
16 inch 2.5 lb. White Perch
14.75 inch 1.9 lb. White Perch
18 inch 3 lb. 8 oz. White Perch
17.75 inch 3 lb. 2 oz. White Perch
And there are a lot more like this if you dig into it.
This is a species (
Morone americana) that has the potential to reach sizes rivaling the largest cichlids. That 7-10 inch size should actually be considered a
bare minimum, not a guideline, for adult size. A majority of pictures seen on-line are at least 10" and many are much larger. As a true bass, it's also going to be much too active for a four-foot tank like a 55 gallon, or even a 75 gallon.
With no idea what research was quoted to determine the 7-10 inch size , or the context of that research, it should not be considered as a reliable source on its own. It is very possible that 90% of the information on the internet is coming from one or two sources which may not be completely accurate outside a certain context and which very well may be quoting each other, creating internal circular validation. These sources may have been studying size inhibition in the species in a certain body of water for all we know (although I do doubt this). Regardless, there can be a wide range of sizes and water conditions for any species. Always do thorough research on any species before determining what conditions are suitable for its maintenance, and always cross-reference multiple sources. A very good place to start is
FishBase. I recommend finding consistent information from at least five independent sources before feeling comfortable.
WYite