Most known clingfish species are from relatively shallow coastal waters, but several inhabit the mesophotic zone and a few even deeper, with "Alabes bathys", "Gobiesox lanceolatus", "Gymnoscyphus ascitus", "Kopua kuiteri", "K. nuimata" and "Protogobiesox asymmetricus" reported from depths of . Because of their small size and typical habitat, it is however suspected that still-undiscovered deep-water species remain. Even in shallow coastal waters many clingfish are highly cryptic and easily overlooked, mostly staying under cover, although there are species that are active and will swim in the open. As a consequence their abundance is often not well known. Several species are only known from a single or a few specimens. Species that appear uncommon or rare based on standard methods can actually be common if using methods that are more suitable for detecting them. Studies of better-known species have shown that they can be locally abundant. As many as 23 individuals of "Lepadogaster lepadogaster" have been documented from a single square metre (more than two individuals per square foot). , the IUCN has evaluated the conservation status of 84 clingfish species (roughly half the species in the family). The majority of these are considered least concern (not threatened), 17 are considered data deficient (available data prevents an evaluation), 8 considered vulnerable and a single endangered. The vulnerable and endangered species all have small distributions, restricted to islands or a single bay. Three "Gobiesox" species that are restricted to fresh water in Mexico have not been rated by the IUCN, but are considered threatened by Mexican authorities.