No, that is not necessary at all. In theory you can come as you are for a canoeing day-trip. The only thing you must remember is water and food. Paddling can be quite hard, and you are going to need some fluid.

And remember the sunscreen. The author of this text forgot it once. Never again!

The canoe has space for storage, and you can easily bring a couple og rucksacks and a cool box. There is a small but real risk that the canoe tilts. Therefore, it is a good idea to bring drybags for the most important things (smartphone, wallet etc.). 
Also cinsider your choice of footwear. You could get water in your canoe - and you might also have to get out of the canoe and push it. Therefore, we recommend bringing spare clothes. Especially dry socks.