However, depending on the context and region, you might hear terms like:
* "Smolt" - This is a technical term for a young salmon that has recently migrated to saltwater, but it's not exactly slang.
* "Fry" - This term is used for very young fish, including salmon, but it's not specific to them.
* "Fingerling" - Similar to "fry," this refers to a very young fish that's about the size of a finger.
Ultimately, the best way to describe a small salmon depends on the specific size and context. You could simply use descriptive terms like "small" or "young" salmon, or you could be more specific about their size.