I have five in a 29 gallon with Danios. Yes they are. they are also the "Brat Pack" of loaches. They will nip anything slow enough to be caught, thats why mine are in a tank alone instead of in the loach tank. They nipped the tails off my guppies, ate the fry(guppy fry settle to the bottom to sleep at night), chased the small bristlenose I had with them.
Now they have Danios with them (too fast to catch), and a larger bristlenose.
Now that said... they are beautiful loaches and very personable
I just bought 2 at the lfs last night. The reason I got them is because I had never seen them in person before and they were really cheap in price($3.99CDN). One of them is a little brat and the other schools with my clown loach, my CAE, and my lemons every-so-often when it can't find its little friend. They are only about an inch in length at the moment and I might buy them instead of dwarf loaches in the furture for my ideal tank. They are so cute.
The only thing they are able to catch is my clown loach or each other and they chase each other around all the time in hopes of finding and defending food they find. It seems that they have made a hierarchy among the three of them.
So all I did to keep my clown loach safe and let it go back to it's original colors(orange and black not orange and grey) was move it to my 36 so it could have a clown loach friend. I noticed that it had started to 'shrink' when I moved it to the 28 and it was by itself for so long. And I'm aware that the 36 is now overstocked(based on the 1"/gallon rule), but it is very lively now.