he's never seemed stressed before, ive had him for several months and there is one other clown in the tank. there was another the same size as him, but it died for some unknown reason. my big clown loach (not really that big, just biggER, about 3") does not seem stressed, and everybody has their own hiding spot. so yeah, i agree it might be pretty full, but there is plenty of structure.
after having the two large rocks out overnight the water is quite a bit clearer now.