Love the game but plz fix – Mermaid World Review

I just got this game and it's very fun but say a want a luau mermaid that's blue and green in traits I make a aqua and a kelp mermaid sing and guess what? I get a aqua mermaid!!! I feel like the singing system is broken. Then I put aqua and coral in and I get the mermaid I want I think the cooler the mermaid is no matter what it's traits is it's harder ti get!!! Plz fix these mermaids aren't even that rare and it's impossible to call them?
Review by AER68 on Mermaid World.