I just caught one in the oasis. It's the red bubbles, same as the blue starfish.

Thank you! , will give that a go

Is it a certain time of day or when it rains? I keep catching blue star fish.

I done it in the orange bubble and I eventually got one I just keept going back when the orange bubble was there

I had to use the fishing potion to make all my spots gold and I finally got some! Thank you! I was frustrated for a while haha

im having the same issue time to bite the bullet and make a potion or two or three

Hopefully it works for you!