Hippocampus ingens occurs at depths of 1–20 m (maximum 60 m) (J. Gomezjuardo in litt. in Lourie et al. 1999), and is often found among gorgonians or black coral (Humann 1993 in Lourie et al. 1999).

This species may be particularly susceptible to decline. The limited information on habitat suggests they inhabit shallow areas (Lourie et al. 1999) that are susceptible to human degradation, as well as making them susceptible to being caught as bycatch. All seahorse species have vital parental care, and many species studied to date have high site fidelity (Perante et al. 2002, Vincent et al., in review), highly structured social behaviour (Vincent and Sadler 1995), and relatively sparse distributions (Lourie et al. 1999). The importance of life history parameters in determining response to exploitation has been demonstrated for a number of species (Jennings et al. 1998).