yes, i do have a hong kong loach in my 65 gallon. ive only had him for about 2 1/2 weeks, so i still dont know much. he pretty much hides around the back and in the driftwood. i see him about once a day. i have heard that they NEED cold water, but i have heard of one in a tank with discus, being very happy. i have mine in a temp of about 78 degrees, and he is fine. they can be in a tank as small as a 10 gallon, as long as there is good filtration (they poop like crazy) and the tank isnt crowded. i think they get about 4 in. max size