I bought a tire track eel about 3 months ago. Only a small one, 5". But two weeks ago he disappeared and I looked all over the floor and everywhere couldn't find him. Today I cleaned out the filters and bam! he pops out! Placed him back in the tank and he swam to his pvc pipe. He shares a 90 gal with 1 3" pleco and a 2.5" oscar. Just thought i'd share!