Is there a midrash that states that all the bodies of water split during the splitting of the reed sea? If yes, I would think that such an event would be recorded in some secular history book? Are there opinions that said midrash should not be taken literally?
You are thinking of the tannaitic Midrash Mekhilta, which says, in the first account, that during the parting of Sea of Reeds, all of the waters in heaven and earth – including waters in pots, pitchers, and drinking cups – split, and that this miracle remained in place until the Israelites were able to escape on dry land. In the second version, there are, twelve paths that opened up in the sea, one for each tribe.
The question also asks about Midrashim. Maimonides wrote in his introductory comments to the Mishnaic tractate Sanhedrin, Chapter Chelek, that people who take midrashim as truth are fools, while those who reject them out of hand are also fools, because midrashim although not true were designed to teach lessons. People need to mine midrashim to uncover moral lessons embedded in the tales. They are parables.