A student investigated the relationship between cleaner shrimp and different species of marine host fish of varying sizes on a tropical reef.
The table below shows the maximum number of cleaner shrimp observed on a single host individual of each species.
| Marine Host | Maximum number of cleaner shrimp observed |
|---|---|
| Moray eel | 6 |
| Nassau grouper | 4 |
| Parrotfish | 2 |
| Damselfish | 0 |
Give one biological reason why more cleaner shrimp were observed on moray eels than on damselfish.
