Mussels in Heartopia are one of those oddly difficult fish to find. They shouldn’t be, considering that you only need to be Fishing Level 4 to reel them in, but they have a very specific set of requirements to spawn.
Thankfully, rainbows are fairly frequent in Heartopia, and they’re one of the two weather events that can summon mussels into some of the lakes.
Where to Fish for Mussels in Heartopia

Mussles can only be found in the Suburban Lakes around the road that separates the players’ home plots and the town centre. There are several Suburban Lakes, but be sure to zoom in on your map and check that you’re definitely fishing in a Suburban Lake and not one of the rivers that connect to them.
Weather and Time of Day

The Mussel in Heartopia enjoys rainbows and rain, and that’s it. You won’t find them during any other type of weather, which is a little disappointing because we Heartopia players are all confused by the lack of meteor shower creatures to catch.
Like rainbows, meteor shower weather events can be completed incredibly quickly. The only difference is that there are rainbow fish and insects to catch, but there aren’t any for showers.
It’s not just the weather that’s important when catching fish; it’s the time of day, too. Thankfully, Mussels in Heartopia come out at any time of day… But that doesn’t mean you’ll catch them easily. I’ve found that during or after sunset is the best time to catch them, no matter what the in-game Collection app says. Once the sun starts to set, go forth and fish for your own Mussel.
The Best Way to Catch Mussels in Heartopia

Buy yourself a few Mermaid Attractors and Mermaid Perfumes from Vanya and keep spamming them until you catch one. Mussels are oddly rare, and it’ll take you a solid 15 or so fish until you pull one up. On my most recent excursion to catch one, I used three Mermaid Attractors and three Mermaid Perfumes and only caught one.
Silly, really, when you can catch fish that are worth a lot more with a lot less effort, but here we are.

