@CyborgShimada
Just to make sure, the fish trap is placed out in the water around Sulani from the sim's inventory by swimming out to a spot away from the shore. I always try to place them over the underwater reefs where you can see fish swimming about. You should get more options on the trop once it is in the water. Then you wait a day or so and swim out and check it to see if you caught anything. I've never had a problem with them but it's been a while since I used one and I forget exactly what the options are but if I remember correctly, the only option you get is to put it in the sim's inventory when the trap is on land or shallow water. If this is what you have been doing and are getting no options on the trap out in the water, then there is something going on. So you might also try a game repair.
I will check this in my game tomorrow to see if am having any issues with the trap as well.
Hope this helps.