The rules are the same as with any other plant - use a pot that's big enough to accommodate the roots without squeezing them into place, but not so large the roots are lost inside the pot. Ordinary multi purpose will do, but if you intend to keep it long term in a pot, then JI No. 2 would be better, but generally, bamboo is not that fussy, though you haven't mentioned the variety. Pot on into something bigger when its rootbound, water as necessary. You won't need to feed it much, bit of growmore in spring really, and initially, if you use new compost, that has some feed in it anyway, which should last it up to six weeks.

We feed more often here in the desert, but that's because we need to water so often--up to 3 times a day, in containers.

If is something like Phyllostachys aurea or nigra then its roots will quickly fill even a quite large pot so a large terracotta or china pot rather than a plastic one which will become deformed in time. Fargesia varieties tend to be a little less vigorous. As suggested, water rather than feed.

I was supposed to have been a Black Bamboo from Thompson & Morrisons BUT the canes didnt turn black, so I don't know the variety? It's not a vigorous grower.
Thanks for all the info folks :o))