Remoras are known for having a modified dorsal fin that acts like a suction cup, allowing them to attach to larger marine animals, like sharks, whales, and even sea turtles.
However, the question "which fish has a smaller attached to it" is a bit ambiguous. Do you mean:
* Which fish has a remora attached to it? Many fish can have remoras attached to them.
* Which fish is the smallest remora? The smallest remora species is the *Remora brachyptera* (also known as the Dwarf Remora).
Please clarify your question, and I'll be happy to give you a more precise answer!