The store I bought them at had a tank full...probably around 20 or 25 of them. They've had them in stock for at least a month. I bought 6. If I had more room I'd love to have a larger group. Oh well. Maybe I'll add to the group in the future when I get a larger tank
One word of advice on horsefaced loaches, they are a nightmare to catch. As they get bigger they become even quicker. When you put them into their new tank, make sure they won't require moving any time soon.
Anyone who's ever had to catch them will tell you this.