Tiktaalik had lungs, a moveable neck, and a ribcage like a tetrapod, but it also had gills, fins, and scales like a fish. So this makes it a transitional fossil between lobe-finned fish and tetrapods.
Tiktaalik probably crawled along the bottoms of shallow freshwater habitats, like ponds and swamps, then waited for prey to come by. But it may have occasionally even crawled up onto land using its leg-like fins to walk.
Tiktaalik was about 3 to 9 feet long, and most likely a predator eating fish, and maybe some small terrestrial arthropods. Tiktaalik could have been related to Panderichthys, which is a similar transitional fossil between the lobe-finned fish and the tetrapods.