The guidebook to Limahuli Gardens explains that "These fish, ‘o‘opu, evolved from saltwater ancestors in the goby family. Although ‘o‘opu live in freshwater streams as adults, their fertilized eggs wash downstream, and young ‘o‘opu must spend their first several months of their lives in the ocean. Four of the ‘o‘opu species have a very interesting and useful adaptation. Their pelvic fins are fused together to form a suction cup which helps them fasten to rocks, the stream bottom, and even to climb waterfalls."

These small native fish figure prominently in Hawaiian sayings. Here are several:

"Ka i‘a a ka wai nui i lawe mai ai."
The fish borne along by the flood
The ‘o‘opu, which was often carried to the lowlands in freshets.
‘Olelo No‘eau #1323

"Ka i‘a haha i kahawai."
The fish groped for in streams.
The ‘o‘opu, often caught by groping under rocks and hollow places in a stream.
‘Olelo No‘eau #1329

"Ka i‘a ka welelau o ke ahi."
The fish that lies on the top edge of the fire.
The ‘o‘opu, wrapped in ti leaves and laid on the hot coals.
‘Olelo No‘eau #1353

"Ka i‘a ko‘eko‘e o ka ‘ili i ka wai."
The fish that chills one's skin in the water.
The ‘o‘opu, usually found in upland streams.
‘Olelo No‘eau #1355

"Ka i‘a mili i ka poho o ka lima."
The fish fondled by the palm of the hand.
When it was the season for the hinana (‘o‘opu spawn), they were so numerous that they could be scooped up in the palm of the hand.
‘Olelo No‘eau #1372)

"Ka i‘a moe kahawai."
The fish that lies in the stream.
The ‘o‘opu.
‘Olelo No‘eau #????

"He nopili ka i‘a, pili pa‘a ke aloha."
The nopili is the fish; love clings fast.
Said of the freshwater gobi (‘o‘opu) of the nopili variety, known to climb waterfalls by clinging fast to the wet stones. It was used by kahuna in hana aloha sorcery.
‘Olelo No‘eau #846

For an excellent resource on ‘o‘opu and other Hawaiian freshwater animals, visit the State of Hawai'i Department of Land and Natural Resources Department of Aquatic Resources. Their page on stream ecosystems comes complete with photographs and explanations of the various varieties of ‘o‘opu found in Hawaiian streams.

Pacific Worlds invites community members to recommend and contribute websites, material, and information to be included in this section. Please send all recommendations to the Director.