Occasionally, multiple fish will be attracted to your lure at once, but you will only be able to catch one of them. During this period of time, the time frame for the fish staying on the hook will be reduced, making it harder to catch more fish. However, if you do succeed in catching a fish, your cast may likely be cancelled and you will not catch the said fish anyway. Additionally, when you unequip and re-equip your rod, one or more fish may still be on the rod. When this happens, casting will result in the line falling at your feet and it will be difficult to fish until this glitch period is over.