The pygmy seahorse (Hippocampus bargibanti) is undoubtedly one of the most well camouflaged species in the oceans, being extremely difficult to spot amongst the gorgonian coral it inhabits.
So effective is this camouflage that the species wasn’t actually discovered until its host gorgonian was being examined in a lab. Large, bulbous tubercles cover this species’ body and match the colour and shape of the polyps of its host species of gorgonian coral, while its body matches the gorgonian stem. Two colour morphs exist: pale grey or purple individuals scattered with pink or red tubercles are found on the similarly coloured gorgonian coral Muricella plectana, and yellow individuals with orange tubercles are found on gorgonian coral Muricella paraplectana.
It is not known whether individuals can change colour if they change hosts, although the ability to change colour according to their surroundings does exist in some other seahorse species, such as H. whitei. Other distinctive pygmy seahorse characteristics include a fleshy head and body, a very short snout, and a long, prehensile tail. This is also one of the smallest seahorse species in the world, typically measuring less than 2 centimetres in height. The male carries eggs and young concealed within the trunk region.
Thanks to AKARlive