Loaches are an intriguing group of freshwater fish, distinguished by their unique body shapes and behaviors. The Cobitidae family encompasses over 200 species of "true loaches," often characterized by elongated, worm-like bodies and barbels near their mouths that resemble whiskers. These barbels are functional, aiding loaches in sensing their environment and locating food in the benthic zones of rivers, ponds, and streams. Generally small, most loach species measure around five to six inches, although size can vary significantly across species.

Loaches exhibit a variety of fascinating behaviors. For example, the Pond Loach is also known as the Weather Loach due to its increased activity before storms. Diet-wise, loaches are primarily omnivorous scavengers, consuming dead plant and animal matter, small crustaceans, insect larvae, and snails. Their dietary and habitat flexibility has enabled them to flourish across Eurasia, with some species introduced elsewhere.

Their captivating characteristics and behaviors, coupled with a peaceful demeanor, have made loaches a favorite among aquarium enthusiasts. The Kuhli Loach, resembling an eel, and the Horseface Loach, with its distinctive elongated face, are examples of popular aquarium species. Loaches thrive in conditions that replicate their natural habitats, with ideal water parameters varying by species but generally including temperatures between 68°F (20°C) and 86°F (30°C), a pH level of 5.5 to 7.8, and water hardness of 3 to 10 dGH, though some may prefer up to 179 ppm. For instance, the Kuhli Loach favors specific water temperatures.