<p>Over the last half century, Florida’s Coral Reef has significantly declined due to bleaching, disease, and hurricanes, leading to increased macroalgae dominance of some reefs. Herbivory helps maintain coral-dominated ecosystems by limiting or mediating macroalgal growth. The Caribbean king crab (<i>Maguimithrax spinosissimus</i>) is an effective native grazer of chemically defended macroalgae, making it a promising candidate for reef restoration given its potential to increase grazing intensity and facilitate improved survival, growth, and recruitment of restored and natural corals via a reduction in coral-algal interactions. However, the influence of chemical cues on mortality and development of <i>M. spinosissimus</i> is unclear. This study examined the effect of four seawater chemical cues on early life history development: (a) control, (b) algae (<i>Dictyota</i> spp.), (c) conspecific, and (d) predator (<i>Panulirus guttatus</i>). Results indicate higher molting rates in control and conspecific treatments, while predator and algae cues increased mortality and reduced molting. Our results suggest that <i>Dictyota</i> spp. macroalgae and predator chemical cues can hinder larval survival (<i>Dictyota</i>: 8.8% survival; <i>P. guttatus</i>: 7.3% survival; Control: 34.7% survival; Conspecific: 28% survival), highlighting the need to take predator density and algal community composition into account when planning for successful Caribbean king crab stocking efforts (e.g., potential effects on appropriate stocking size, density, and frequency).</p>