The recommended tank size for the Kuhli Loach is any size setup that you can comfortably maintain in water. A medium size tank will allow you to provide more food and water conditions that your fish will enjoy and will result in healthier, more robust fish. A very smaller tank will produce smaller, less healthy fish and is more difficult to maintain. A small tank is best for beginners while a larger tank is ideal for more advanced hobbyists. It can be a challenge to keep a small loach in a very small aquarium, so a medium tank is better suited for people who want to own Kuhli Loaches.