I had a snowflake eel a few months ago. Just as a precaution, I would watch your clowns. The snowflake I had, which was not very big, came into my tank and started using my fish as his food source. During the night, he would hunt down my fish and before I could net him out of the rock work, he killed my v-tailed grouper, niger trigger, and blue headed wrasse.
Mine did not try to escape very often. After I put food in the tank for him though, he would immediately try to jump out of the tank after he was done eating. Other than that, he pretty much just hung out in the rocks and decor.