Do all the species in the old world that can bleed bleed red?

[Urgat]

http://www.dinosoria.com/hominides/singe-5.jpg
That's blue, bright, shiney blue, and that's not the fur, that's his skin. Where's the brownish tint? Where's the vital reason for it to be blue too, by the way? Don't know the name in English, it's a mandrille in French, if you wana look it up (though I guess you already know about it, it's nothing new or rare).

As for beastmen, when people say beastmen, they usually refer to Gors, which are clearly a stable species of their own just like skavens now.

[Arnizipal]

As for beastmen, when people say beastmen, they usually refer to Gors, which are clearly a stable species of their own just like skavens now.

I don't think they're all that stable. Backgroundwise they could be made up of just about any creature (goats, bulls, wolves, rams, various insects...) instead of the generic goat-headed beastmen we see in the game.

As for greenskin blood, this is the quote:

They have a tough and waxy green skin, which becomes scabby, gnarled and even tougher over time. Their blood varies in colour from red to purple or black and is unusually think, pungent and sticky.

[Urgat]

I don't think they're all that stable. Backgroundwise they could be made up of just about any creature (goats, bulls, wolves, rams, various insects...) instead of the generic goat-headed beastmen we see in the game.

Not gors, no, gors definitively are the goat-haded ones. Anyway, when was the last time beastmen as an army were seriously decribed as anything else but gors+ungors+minotaurs+centigors in WFB? I think it was 4th ed. Mutants and other random beastmen (the good old flyman, dogman, etc, they all used to have one or two minis) have always been an ignored element of the beastmen fluff in WFB, it's really more a RPG aspect of them, much like cultists are completely absent when they are supposed to be the greatest actual chaos threat, the every-day hazard.

As for greenskin blood, this is the quote:

Yeah, I remember that. It's good for me, blood that is not red just doesn't get has the same impact (see guys splattered in green or orange ooze in Starship Troopers, or the Predator's phosporescent green... yeah it's fun and alien, but yu don't go and think "omg blood!"). Blood needs to be red, for me

[The Warmaster]

Well you don't necessarily need haemoglobin; you can live very well with blue or green blood, too. There are blood molecules that act very much akin to haemoglobin but are instead copper-based, for example.

Indeed, Octopus' bleed blue.

Yup, this is because they use haemocyanin instead of haemoglobin (which is blue when oxygenated because of the copper content). It's not so efficient for larger organisms, but I'm sure you could make some sort of alternate version that's better for it. A story I have planned out has a species on a copper-rich world that uses haemocyanin, which I think could also work for a metal-heavy biochemistry (e.g. Turians from Mass Effect).

[Verm1s]

Reptiles are another matter cause they have scales. Scales isnt living tissue, it doesn't need blood, thus there are no veins in it and no tinge of red.

Newp. Not quite.

http://www.anapsid.org/basicdermatology.html
http://www.whozoo.org/ZooPax/ZPScales.htm

Anyway, why do tinges of red show through your dead fingernails?

Don't know the name in English, it's a mandrille in French

Same in english, but without the E.

http://en.wikipedia.org/wiki/Mandrill

[N810]

Well the forest goblins giant spiders wouldn't have red blood...

[slirgy]

in the gotrek and felix anthology it says something about gotrek figting skaven and in the end it says something about black blood spattered on the floor ( it think the story was the tilean talisman but im not sure)

[Arnizipal]

Well the forest goblins giant spiders wouldn't have red blood...

I don't think spiders even have blood...

[Verm1s]

I don't think spiders even have blood...

http://en.wikipedia.org/wiki/Hemolymph

[Bingo the Fun Monkey]

While I understand that the official GW statement is that Orcoids bleed red to look cool (thanks, Dirty Steve), for my own imagination I've taken a different route. Orcish skin, when bled dry, is yellow. Their blood is dark blue, but turns dark burgundy when exposed to oxygen. I like to think that it's lump and sticky too, with a slight sweet floral and offal scent.

[Arnizipal]

http://en.wikipedia.org/wiki/Hemolymph

So not really blood then

[N810]

Huhuhhh....

Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods (including spiders, crustaceans such as crabs and shrimp, and even some insects such as stoneflies) and is analogous to the fluids and cells making up both blood and interstitial fluid (including water, proteins, fats, sugars, hormones, etc.) in vertebrates such as birds and mammals. In addition, some non-arthropods such as molluscs possess a hemolymphatic circulatory system.

[Verm1s]

So not really blood then

Well, quite.

Huhuhhh....

Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods (including spiders, crustaceans such as crabs and shrimp, and even some insects such as stoneflies) and is analogous to the fluids and cells making up both blood and interstitial fluid... in vertebrates such as birds and mammals. In addition, some non-arthropods such as molluscs possess a hemolymphatic circulatory system.

[N810]

so like I said bug blood.