Since this card's ATK is so low, having to Normal Summon it to use its search effect puts the controller's life points at risk. Immediately replacing this card with a stronger monster makes Mermaid Shark safer to use. Here are some ways to do this:
Try Summoning it after one or more other Level 1 monsters so you can overlay them into a Rank 1 Xyz Summon.
Summon this card, then Tribute it to use the effect of a WATER monster on the field (like "Mecha Sea Dragon Plesion") or in your hand (preferably for the Special Summon of "Sharkraken" or another strong monster).