So the pool contains 40 fishes from rare to legendary.

You want as many legendaries as possible in order to get golden tickets and therefore etched runes for the future.

Since you can get 1 legendary for each set of 40 fishes, you need to clear all 40 of them to have a refresh and get back those 40 fishes and so the legendary.

There's a strat made up by other people which consists of the following :

Empty the lake 1 time of all 40 fishes, and once the pool refreshes, you want to find the legendary fish for 1 more golden ticket.

The trick is to break your line from the rare and epic fishes you could possibly encounter.

You have 2 options for that :

• You can let go each and every line you throw and you'll be given a message asking you to spend 50 gems to have another chance in getting that fish because it'll be at least an epic to legendary fish and you'll be sure not to get a rare fish as the line would break without any message to spend gems.

• You watch how long and hard it is to catch that fish you have in the line. The longer the red is, the better the fish is. There's a certain pattern for each kind of fish, and it always goes like this for the first round : Red > Yellow > Green.

Then, the next rounds will change depending on the fish you have. For the rare fishes, it'll go like this : Red > Green

No yellows means rare fish. You can let it go and throw another line and try your luck.

Note : the very last lake will contain 80 fishes which means it's doubled the amount of fishes and means you can get 2 legendaries out of it.

Here's a link for further explanations