What kind of turtle are you going to house?
Do the American Cichlids require any salinity in their water because I believe that Africans do and depending on what kind of turtle salty water may not be good for them.
Also, how big is the turtle and how big are the cichlids?
If all that is cool, then I think that the 3/4 full idea is the best and you may be able to buy or construct a platform on one end for the turt?


