Cactus identification

Hi all,

Hoping someone might be able to help me. I was given a cactus as a gift a few months ago and I have been unable to identify the exact type (picture below), it's about 50cm tall. I have tried to look after it as best as I can up until now but think I need someone to explain exactly how I should do this as the tops have started going a slightly lighter colour.

Any help greatly appreciated!

Thanks,
Dan

 

Euphorbia cactus ?

 

Possibly the Acanthoceerus ...

On-line Guide to the positive identification of Members of the Cactus Family

 

I tend to go for Euphorbia, dont think it is a cactus as such.
White sap would confirm one way or the other.

Possible, but not sure
Euphorbia triangularis - Wikispecies

 

Sorry missed the part about the looking after it.
It needs water and feed at this time of the year, and good strong light, even direct sunlight.
Keep it much dryer in winter, and again as much good natural light as possible.

 

Thanks all!