Of course, if there's a stick, that would be ideal. However, without the Seal of Truesky, a knife is undoubtedly more practical; after all, its sharp edge makes it relatively simple to use, whether for killing or cutting down monsters.
Standing by the lakeside, you can clearly see a large group of fish with spiked backs swimming not far away in the lake. Using the "Basic Monster Identification Technique" that every novice possesses, you discover that these fish are astonishingly at Level 20.
Without hesitation, you slash swiftly at the closest, larger fish with your knife. The ambush proves effective, yet the fish doesn't split into two as you imagined. Its bones appear incredibly tough, and before it has time to react, you need four consecutive slashes to finally kill it.
By now, you've ventured deeper into the water, surrounded by sharp fish spikes.