Nice Kuhli, lunasmile. Like Wendie has said, try and get yourself a few more to keep it company. I also think it'd be better for your loaches if you switched to a finer substrate as your gravel looks a little bit large and sharp. You should consider changing over to a smooth smaller-sized gravel, or better still, aquatic sand. Your loaches will thank you for it!
You're right Emma. That stuff has sharp edges. I use sand and very small smooth river stones with my guys. I am just waiting for the white sand to settle in one tank now. I've got about 21 spread out over several tanks.
i agree with everyone. it is a black kuhli and sand is the best. in my tank i have many of these guys (love them). count them as 1.5" of fish and not 3" (in the gallon per inch of fish rule). i use small rounded polished glass for mine, they're cool with it. not sharp at all.