you take a breathalyzer test to see if it hasn't been drinking seaweed grog, then you see if it swims in a straight line, lastly, it can blurble the fish alphabet backwards
God grant that I may live to fish until my dying day,
And when it comes to my last cast, I most humbly pray,
When in the Lord's safe landing net I'm peacefully asleep,
That in His mercy I be judged, as big enough to keep.