Not many true fishes from temperate marine environments, are traded in fish stores, online or otherwise. But sometimes a popular public aquarium species, the Garibaldi (Hypsypops rubicundus) is encountered for sale, although it must not be kept in a tropical reef tank (because the optimum tempertures for a reef tank, re 27 to 29 degrees centigrade). This species may also be called the catalina goldfish on account of its coloration; the Garibaldi is not related to the goldfish, which is a carp, because it is the worlds largest damselfish - it grows up to 12 inches long, or 30 centimeters - and is therefore a perch. 'Catalina' refers to an island near California, and the Garibaldi has a range from California to Baja California, and nearby islands.
There this damsel inhabits shallow seas, were there are rocky bottoms, and especially rocky reefs on exposed to semi-protected coasts with clear water; the complex natural aquascape of the reef provides plenty cover for the Garibaldi to set up territories and hids. The species is less often associared with kelp, where it eats encrusting organisms on the kelp, and the juvenile Garibaldis are hardy enough to be found in intertidal rock pools. One of the oddities about the Garibaldi, is that the mature males are about 2.5 centimeters or 1 inch longer than the females. which is the opposite of what is normal in the damselfishes. The males guard the nests at which time they become famously pugnacious.
Besides the fact that the Garibaldi is not a tropical fish, its diet would make it unsafe in a coral reef. Their broad spectrum diet definitely includes anemones and gorgonians, and they are able to consume both branching and encrusting growth forms of sessile fodder. As omnivores they do consume red, green, and brown algae, with a preference for fleshier red kinds. Although their diet varies depending on variables, Garibaldi on average are thought to feed mostly on such macroalgae, anemones, annelids, and sponges; they also consume sessile and other benthic animals, including arthropods, molluscs and brittlestars. Such an animal is best categorised as a generalist and an omnivore, so they should not be problematic to feed in the home aquarium, although based on studies of wild Garibaldis, their diet should have a little more animal protein than vegetable matter.
In the aquarium, their aquascape ought to be one of complex rockwork, and it should provide them with suitable caves for retreats. This species, like other benthivorous damselfishes, is quite territorial, so only in large aquaria should members of this species usually be cohabited. They are not really a comunity fish for this same reason. Living in Monterrey Bay, in the north of Garibaldi distribution, the sea temperture is 12 to 16 degrees centigrade. However in late summertime, the fish from the southern end of their range, experience water tempertures of 21–24 degrees centigrade. Thus the Garibaldi can live without a chiller if the ambient room temperture does not exceed 24 degrees; it is reccommended that a habitable room in a house be maintained at 18 to 22 degrees, but heatwaves do occur, and purchasing a chiller is reccomended if the room temperture is not especially stable - but it would probably not need to be running all of the time.