How bad does getting bit by an oct? Scale from 1-10, 10 being leg getting cut off. Is there a first aid kit for being bit? Also, does it happen alot to people who own them? I just want to know what I am about what I have to face when I bring mine home. Thanks -D-
The bite depends on the species, age and other factors.
In the case of the bimac, most people experience only a curious little nibble, not as bad as a bee sting. I don't think anyone has reported even being nibbled on by a briareus. (Please respond if you have!)
The dwarfs can be agressive and seem to have more toxin in their bites. I belive it was Greg (cthulhu77) who reported pain for several hours. Larger octopuses have larger beaks and therefore larger bites, but many are not aggressive. Neogondactylus mentioned O. cyanea as a biter.
A few are defensive biters, like O. rubescens. Still, I watched someone handling small O. rubescens (mantle about the size of an orange) and he recieved an "ouch" type bite, but also not too bad.
It was not a real attack.
The thing to watch for is an allergic reaction to the toxin, like that for a beesting. I don't think you should encourage octo nibbling or biting, but if it happens, you'll most likely survive.
It has also been suggested that octopuses will deliver different amount of venom depending on the situation and the personality of the octopus. I have known people to get bit by rubescens and have not ill effects beyond the mechanical puncture wound, and have also known people to have a strong reaction. This could also be an allergic reaction, however it seems a higher percentage of people get "bad bites" than you would expect from an allergic reaction.
All that being said, if you do get bit, and are having a bad reaction, the best first aid seems to be to simply pour as hot water as you can stand on the bite. This can denature the proteins in the venom and lessen the effects. For more info I would suggest reading "An octopus bite and its treatment" by Roland Anderson, which can be found at http://www.nhm.ac.uk/hosted_sites/tcp/octobite.html
The bites have received from O. cyanea were defensive, but it didn't take much to induce them. Same with O. rubescens.
I think that one point that should be made here is that we know very little about which octopuses have venom that can affect a human and which do not. There is discussion that one or more of the "mimics" might be venomous and O. motuti probably is. Given the number of undescribed species still out there, it is probably not a good idea to give an octopus that you do not know a chance to bite.
I would also suggest that you spend a little time exploring some medial indexes searching for infectious agents found in aquaria. Some are quite nasty and it should convince you that it is not a good idea to have a fresh bite that breaks the skin come in contact with aquarium water.
Also, I have heard that in the not to distant future there will be published reports of other deadly cephalopods besides blue-rings.
Roy is right to bring up the possiblity of infection from your aquarium. Last year I got one because had a small cut on my finger near the nail. I wasn't bitten, I just exposed myself to the water. Eventually I had to take antibiotics - since then I've been more cautious.
I think most people can avoid octo bites by watching the position of the octopus and your hand. Don't let it float down on your hand. Encourage octo play that involves the tips of the arms. It won't necessarily bite, but it might.