Radak: Water surrounded me to the point that my Nefesh almost departed, until the fish swallowed me. This is like "Ki Va'u Mayim Ad Nafesh" (Tehilim 69:2).

Malbim: This was when the first fish vomited him out. This does not refer to the water on the surface of the sea, like the first time. Rather, "Tehom Yesoveveni" ? the fish was deep in the water, and vomited him out.

Targum Yonasan: The Yam Suf was suspended above my head. Rashi ? Hashem showed to him Yam Suf and how Yisrael crossed. The two eyes of the fish were like windows; [Yonah] was able to see everything in the sea. Radak ? some say that Yam Suf enters the sea at Yafo.

Radak: Suf is reeds. Some grow on the bank of the river or sea. Therefore, [Yam Suf] is called Suf, because much Suf grows on its bank. Some grows on the sea floor, at the base of the mountains ¹ . It is thin and long, and wraps in the heads of fish. It was on the head of the fish that swallowed Yonah; it was like his head, the entire time that he was in the fish.

Malbim: Yam Suf is the water above the depth, which is called Suf. The fish took him by the way of Yam Suf, and from there to Ninveh. "It was bound on my head" ? the sea was above his head, since he was in the depth.