Sea spiders are not true spiders, but they are spider like with most of the 1300 species having 8 legs. A sea spider has a proboscis for slurping up the insides of the invertebrate animals like anemones that they feed on. They range in size from fingernail sized to an Antarctic species with 750 mm (almost 3 feet) long legs. They are weird and fascinating creatures that most of us probably haven't seen. Do any zoos or aquariums have them? There is only one picture of a live one in the gallery, an Ascorhynchus japonicas at Sea Paradise in Japan photographed by devilfish. They seem like an interesting group that might get some visitor interest if exhibited with panache. The lack of the species in aquariums might mean that they are difficult to keep alive, or acquire, or just haven't gotten interest from the aquarium community. Does anybody have any insight into this? Here is the picture of the sea spider at Sea Paradise taken by devilfish: Sea spider, February 2016 | ZooChat
the International Antarctic Centre in Christchurch (New Zealand) used to have an Antarctic aquarium, amongst the inhabitants of which were various large sea spiders (as in hand-sized). That's the only place I've seen them in an aquarium, although I've seen tiny ones occasionally in the wild in New Zealand. Apparently they turn up regularly in reef aquariums (presumably both private and public): Pycnogonids, Sea Spider Hitchhikers In Reef Aquaria
A number of Japanese aquariums (not just Sea Paradise) have kept, or keeps, medium sized species from deeper waters. Large species were (are?) also kept at aquariums in Antarctic research stations, but I don't know if they still allow ordinary visitors. As mentioned by Chlidonias, various species sometimes hitch along in reef aquariums, but are generally not appreciated. Both because they are tiny in size (difficult to truly enjoy them) and tend to feed on various sessile invertebrates that reef aquarists appreciate.
The species kept at a few Japanese aquariums is Ascorhynchus japonicum (the species also mentioned in David's first post with a small typo). This is the largest, body width up to c. 2 cm (~1 inch) and leg span c. 15 cm (~6 in), fairly common sea spider found at "collectable" depths in the oceans around Japan and therefore a logical first choice of species. It is found in fairly deep waters, typically at least a few hundred meters (it has exceptionally been seen as shallow as 50 m), in the North Pacific; off the NW United States too. Sea spiders are generally very poorly known and I don't know exactly what this species feeds on in the wild or is fed in captivity. However, sea spiders in general feed on sessile invertebrates such as sponges, sea anemones, deep-sea corals, etc, and they tend to have extremely low feeding requirements, being able to live for long periods without feeding at all. The ones kept at Antarctic research centres, which could (still can?) be visited by Antarctic tourists is Colossendeis.
An Antarctic aquarium would be worth visiting: seals, penguins, ice fish and such inverts. I never saw sheathbills either but they ought to be easy and appealing: omnivorous, intelligent etc. A whole continent neglected?
Bumping this as I visited Multimar Wattforum in Tönning, Germany this July and to my surprise saw a sea spider (Pycnogonum littorale) on display. So they are apparently kept elsewhere than Japan and Antarctic research stations. However, I don't know if they've always kept sea spiders, or if I was lucky with the timing of my visit.
Do you have any photos of the sea spiders and the tanks? I visited the Antarctic Centre over a decade ago and didn't take any photos. I remember a tank with small greyish-white fish in it, possibly Bald Notothen? There were other tanks but what was in them evades me.
JAZA's listings for Tokyo Sea Life Park mention Ascorhynchus japonicus, but I did not see it when I visited. I don't know how up-to-date JAZA's listings are so I don't know if they still have it.
No, it is pretty frustrating for me too! They had fish, sea spiders, and nudibranchs - but I don't which species any of them were because I didn't note any of them down or take any photos.
I found some pictures of the tanks! Look to be notothens, possibly Bald Notothen and Dusky Rockcod? Antarctic Centre Christchurch The sea spider Antarctic Centre - sea spider Perhaps it would be possible to send an email to the Antarctic Centre asking what species they have currently?
They took out the aquarium over a decade ago - certainly before 2010 but I can't remember exactly. The only live animals they have had since then are the Little Blue Penguins.
