Just a suggestion,if you upgrade to a larger tank,the turtles size will skyrocket.
when i got mine they were 1 inch from shell tip to sell tip.now the biggest is 3-3.5 inches,
i went from a 10 gallon to a 45 and this happened.
Watowdow's 30 gallon freshwater fish tank, 30 gallon
Pyzik's 30 gallon freshwater fish tank, First Tank