Engineer Goby (Pholidichthys leucotaenia)

Don't be fooled by the tidy black-and-white stripes — the Engineer Goby is less a reef housekeeper and more a full-time excavation crew. Those bold juvenile bands are thought to mimic schools of toxic catfish, discouraging predators while the young fish stay close to the bottom. Give one some sand and rubble and it goes straight to work, tunneling beneath rock and shifting substrate grain by grain until the aquascape looks a little different than it did the day before. Colonial and peaceful by nature, they cause no trouble for tankmates, but a growing adult pushing a foot or more in length is a genuine landscape engineer, so anchor your rockwork well before it starts remodeling underneath it.

Care level: Easy · Temperament: Peaceful · Max size: ~12" · Min tank: 55+ gal · Diet: Carnivore, meaty foods