I get the same type of problems, I take care of a few fish tanks at the elementary that i intern at. One teacher was keeping a red eared slider that is probably 5 inches across in a 10g with 20 rosy red minnows that she had bought as feeders. She was a regular 10g hanging filter that obviously wasnt meant to do the job with a turtle, and she hadnt vacuumed the substrate since she go the thing like 9 months ago. The water was so cloudy you could hardly see the turtle. After a few weeks of massive water changes and relocating the majority of the minnows you can actually see the turtle. And she was completely confused as to why the turtle wasnt eating the fish that were much too large for him and last week she bought turtle pellets that were also way to big for him. She keeps telling me that he is a "big" turtle so he should be able to eat them. And I keep telling her that if the food is the size of his head and larger it will not fit well down his throat. They went of school break for 3 weeks and didnt clean or feed the poor things. Not to mention her other 40g hex tank with cold and warm water fish mixed in with no heater. I have no idea how these animals are still alive. So I go in twice a week and do maintenance in the effort to make them as comfortable as possible.
