I’ve had this one loach for about 12 years. It’s about 6cm long. I had a 4 foot tank but now I have downsized to a smaller tank 60 x 50 x 35 : 105 litres. It seems healthy, although quite dark in colour. Hides a lot but will swim about when lights are out. The problem is, although I like my loach, it doesn’t seem happy. When go quietly to the tank - which has plants and about 20 tetras, it will often go ballistic. I’m often concerned it will damage itself. It makes working in the tank very difficult. Just seems now like it should be in a larger aquarium. I would however, hate for it to die in the hands of an amateur. What would you do ?