Clown Loaches are very social fish and it's not recommended to keep less than three together. There is someone here than has just one (Tom?) and it's doing well. You just don't see their cute behaviour. They sleep together, swim together and squabble over food

They also get very Large, up to 12-14 inches.
My first experience with them- I bought three and one died, replaced it and it died so I left them alone as a pair and they were great. They started out in a 30 gallon long and in the first year grew to be six inches and very fat. I did 2x weekly 50% water changes. They insist on clean, highly oxygenated water. They went to the 75 gallon and grew another 1-2 inches. I was doing 2x 25% water changes. They had two filters amounting to a little over 800gph. When we moved they didn't make it. There are pictures of them in my gallery I think.
All this to say, they are wonderful fish, grow fast the first year and will need a much larger tank at that time. They are heavy waste producers and you have to keep an eye on your water parameters. They are ICH magnets and good barometers of whats going on in your tank because if something is going on in your tank they will be the first to show it.
I now have more Clown Loaches. We bought 6 tiny ones at Petco still n the shippers bag. Two were so tiny we lost them and one of the remaining four is still tiny don't know if it will make it or not but the other three are doing great. all are 2 inches or under

Heres some great info on them
http://www.loaches.com/species-index...a-macracanthus
The article says they are nocturnal and they are to some extent but it doesn't take them long to recognize that they will be fed if they come out during the day.
Was going to link the thread with the tank pics and little clown pics but evidently when Mike moved it over the pics didn't come with it. If you like I'll look for them.

Sorry for the book, you know better than to get me to talk about loaches

Caril