One of the best clean-up crews for turtle tanks is a combination of snails and shrimp. Snails, such as Nerite snails, help to keep the tank clean by eating algae and leftover food. They also help to aerate the substrate. Shrimp, like Amano shrimp, are great for cleaning up any uneaten food and detritus, ensuring a cleaner tank. The combination of snails and shrimp creates a balanced ecosystem and helps to maintain water quality. It's important to make sure the turtle tank is adequately sized to accommodate both the turtle and the clean-up crew. This will help to ensure a healthier and cleaner environment for your turtle.