Aggressive Clown Loach

[xxBarneyxx]

anyone explain why I've been able to grow one very large happy clown loach called Clarence in my small tank. I will post a photo soon.

I'm afraid you have grown a very large clown loach but happy is a subjective term and just because it is alive does not mean it is thriving.

I agree that the tank is way to small for clown loaches and overcrowding could have been a problem. They are relatively social in my experience but if they dont have much space then it could have caused problems.

What are your water parameters like (ammonia, nitrite, nitrate and temp)? Clown loaches are pretty sensitive and poor water conditions may also have lead to aggressive behaviour, also if one was ill the others may have turned on it. I'm not sure about the meds you used but Clown loaches are also sensitive about meds as well because they do not have scales.