Bananogmius is an extinct genus of ray-finned fish that lived during the Late Cretaceous period. It was found in what is now Kansas, USA. It had a thin body, similar to that of a modern angelfish, and dozens of small teeth. However, it is best known for the tall dorsal fin on its back, which looked like a sail. It is unknown what this sail would have been used for.
In The Land Before Time
Five Bananogmius briefly appear in The Land Before Time III: The Time of the Great Giving, where they are seen franticly swimming around in a pool of drying water formed in a dinosaur footprint. One leaps out of the pool and flops into the nearby river, where it swims towards a group of drinking Iguanodons. It is unknown what happened to the other four, however, it is likely that they did the same thing in order to stay alive.