I've tried keeping some crays in my tank before which seemed to be a mistake. I bought a couple red crays (plain ol' little things, I'm not sure on the species). After my first which would climb my hornwort and sway in the current at the top, I bought it 2 buddies. They proceeded to trim my new plants for me, right at the root. I've noticed many people keeping these little critters in planted tanks. Whats the trick to keeping them from destroying plants? I fed mine blanched cucumber and pellets daily and they still pinched up my plants!