How poisonous are foxfaces?

[DanG]

So my dumbass maroon clown got stung again by my foxface. The clown is a good 6 inches and very territorial and the foxface is closer to 3 inches and pretty timid. I've got lots of rockwork and it's a big enough tank that they can stay far apart, they just chose not too.

What sort of tolerance do fish that just don't learn have to a sting like this?