This is why I love AC's I got an AC 20 on my 15g peacock eel tank and there is no room for him to get in lol. I took out the carbon and filled it with biomax. I am looking for a way for him to not uproot my plants now though... I am thinking putting a large piece of slate under the sand and drilling a few holes for fishing line and tying it to the plants. I will probably also build a below-sand PVC tunnel. Similar to prairie dog tunnels so he will have a place to hide, hehe rather than burying himself in the sand.