Very very slow growers, I found that my monsters would outgrow them and then one day become lunch. If you do get them, they do really well in schools or packs.
I recently traded in my pink kisser - harrassing the other fish - for three clown loaches. One of my loaches died recently, but the other two are a blast to watch. I did hear that they grow slowly...so, I hope to have them for a long time to come.