That One NPC

Neato! Look at all the fishies! And a mermaid too! Though looks like the fishing area might be a bit over populated to me? Maybe some kinda of fish should be rarer to show up? I donno, balancing is hard.

Yeah that was a mass sprite test more than anything. Not even all the fish are present here.

All fish types using the default, coastal background.

With his fishing game, the idea is definitely to have a higher degree of clutter so that you can't just grab the fish you want with the bait that works, every time, only worrying about line breaks. Instead you want to balance bait diets so that in order to catch a mermaid, you need an Elder Leaf, or Jelly Belly treat. However, lingering too low will cause lobsters and crab to consume the bait, just as other fish will eat it during the pursuit of the mermaid.

This creates a dynamic of patients in waiting out fish positions, as well as mastering the power meter, and control over your active bait line.

@Kayzee

Other examples from my tinkered system are chests and relics (mainly for games with appraisal/identifying systems that can later turn a generic "relic" item into a random item, so as to avoid disrupting the fishing session via common event processing) only react to the "Salvage Hook" bait type. This bait has 50 weight so it plummets to the bottom quickly. But it's not just there to nab chests and relics, it can also accidentally pull up clams and lobsters.

Chum is used to attract sharks mainly, but other predatorial, meat eating fish like the bloodtail and razorfin, or even eels will consume chum bait.

Each bait type has a number of fish of varying values and sizes that will take it, meaning you have to prioritize bait types with desired targets and strategize around your tackle box and the playing field.

There are 16 catchable species, and 12 bait types, 4 rock types including a mermaid one for mermaid ponds, and 3 chest types. So a lot can be done to flesh out this fantastic minigame that also doubles as a potential utility distraction.