I have a lfs who is Octo hunting for me. I am looking for a Hummelincki because I believe they are Diurnal and warm temp creatures. His supplier from Florida says he has a Vulgaris but I thought these were more of a cold watet animal..thoughts?
Suppliers rarely know the species of an octopus. If the animal if very young (and occasionally not so young), even experts has problems identifying them. From what we have seen, O. hummelincki (formerly O. filosus) is often tagged as either O. vulgaris or O bimaculoides. If it is from the Caribbean, it won't be a bimac and very likely will be a hummelincki (there are very few places to legally collect bimacs for resale so if you can find out the origin of the animal it give you a big clue. If they won't say, ask about Haiti, sometimes they will confirm if they know you know they import and you make it clear you are concerned about a proper environment). O. vulgaris is another story and can easily be one or the other. Most US collecting is done in the Gulf or along the Southern Atlantic and will be warm water species but, again, do your best to find the original body of water. From the little bit I have been able to put together, most of the vulgaris will come from areas north of the Keys (but I have had one from the Key area) and from the Gulf of Mexico. However, this may be more because of collector location (usually shallow reef in the Keys) than anything to do with water temperatures or north/south locations. The US southern O. vulgaris (warmer water animals) have been noted as being much smaller (needing 130+ gallon tank) than the Mediteranean (needing 300+ tanks) but we really don't have much else to go by. I had had one that never grew larger than an O. briareus but was prepared to move her to a 140 if she out grew the 65.
The point of the monologue is to stress that we are never sure of what will show up but that you may be slightly better informed on what to expect if you can get the seller to answer a few questions. In the case of vulgaris vs hummelincki, a major plus is to ask if it shows a pair of round spots below the eyes. A positive on this will highly suggest hummelincki over vulgaris.