Murky vs Junkrat
Junkrat can be easy to lane against if you can dodge his grenades. While Junkrat is fragile killing is difficult because of his escape. Junkrat does not have mana either so only way to get him to retreat is to get him really low on health.
Fish Tank will not help Murky late game. But you Junkrat will be running from you not the other way around. Slippery When Wet might be usefull to chase Junkrat down and slap him with a fish.