Here are some tips for designing a logo with the letter "S" and a fish:
Simplicity: Keep the design simple, so it is easily recognizable and memorable.
Color: Consider using colors that are related to water or fishing, such as blue or green.
Typography: Choose a font that is legible and appropriate for the industry, such as a sans-serif font for a modern look.
Symbolism: Incorporate the image of a fish in a creative way, such as incorporating it into the shape of the letter "S".
Versatility: Design the logo in a way that it can be easily used across different mediums and sizes.
Remember, the key to a successful logo design is to keep it simple, memorable, and relevant to the industry.