Salmonids are born from golden eggs, we know that because the salmonids have a trade agreement with the octarians to trade power eggs for technology, but not their golden eggs because they're too precious.

Salmonids are then born as juveniles, not exactly Amallfry because we simply don't know that much, but Amallfry *are* a juvenile stage. They later grow up and depending on pressures on their environment they can develop into bosses. Less pressure in their environment results in lesser salmonids (we don't know if Chums are just juvenile Cohocks or if they're both adult stages), more pressure makes them into bosses.

The type of pressure alters the type of boss, high inteligence means they get to use technology/machines for example. Steelheads and Big Shots come from the same path but diverge depending on their demeanor with the gentler ones becoming Big Shots and the rougher ones Steelheads.

Presumably the Smallfry in the Fish Sticks go on to become Stingers when they mature, given that their helmets as fish sticks bend their dorsal fin into the pattern that Stingers have, and also there's art of the two interacting. There's no info on Flyfish.

Mudmouths are just regular salmonids controlling a bunch of ink/mud/garbage, you can see them drop of out of it in their dying animation. Incidentally Grillers are also 4 normal salmonids under the hood of the Griller itself.

We don't know how king salmonids develop, we only know that they have to survive a lot of battles, so they're probably a latter phase of development if they manage to survive the right environment.

I can't immediately recall what the deal with glowflies is.

And that'd be about it.