First, it must be Winter time in your town (having it snow). Then, on a random day, a string fish (it is pretty big) might be in the river, and only in the rivers. The string fish will not be in the ocean or in the water fall area - only in the rivers.
Here is the info from the Animal Crossing City Folk guide
Sting Ray:
Location: Sea
When: August to December
Time: 4am to 9pm
Shadow Size: Huge
RARE
Sell: 3,000 bells
It is found in the river and is very big. You catch it like any other fish. They are found only in Winter (December to February). Tom Nook buys it for 15,000 bells.
Stringfish come out in the winter and they are in ponds/lakes.
String Fish are found in the River between December and February, between the times 4pm to 9am.
String-fish
Time: Morning/Evening/Night
Month: December-February
Location: River
Price: 15,000
No, you cannot catch a shrimp on Animal Crossing (for the Nintendo Gamecube), nor can you catch a shrimp for any of it's successors, Animal Crossing: Wild World and Animal Crossing: City Folk.
No.
It will be in the sea on a rainy day.
There is many bugs/insects on Animal Crossing and the link Below will help you see what you can catch.
yes, they live in the riverpools in your town
You can't catch a spider on any animal crossing game. It knocks you out. Put away your net when you catch sight of a spider or scorpion. Now READ THE ANIMAL CROSSING CITY FOLK BOOKLET!
There are no roaches in Animal Crossing City Folk and you cannot catch the roaches in your house on any game (You cannot equip tools inside). On Animal Crossing games other than City Folk you can catch roaches anytime of year. Just walk up to the roach with the net in your hand and press the 'A' button to swing your net. Any roach you catch will sell for 5 bell at Nook's. Hope I helped! Happy Animal Crossing! ^.^
Usually dusk I find them on trees
In Animal Crossing: Let's Go to the City for Wii simply go to the bus stop in your town and interact with the sign/ bus schedule on the little platform and the bus will appear in seconds to whisk you away to the city. There is no bus to the city in Animal Crossing: Wild World on DS.
You cant go to the city on animal crossing wildword.Only can you go on animal crossing lets go to the city (animal cossing city folk).
Its really hard but you catch them in the rivers during spring or summer.
July-August All Day in the Ocean