Probably round worms if they were long and skinny... I've read that valbazen can be given in water. I know TS carries Wazine, which is only for roundworms. I've used that with great success, but I've only dealt with roundworms, and I KNEW it was roundworms.
You could give that a try first, if it'll be a while before you're able to get the Valb. Google roundworm pics, and see if that's what you saw...
Good luck!
Oh...I'll add that the downside of giving any of these things through the water is that you're never sure of the dosage your birds recieved. If a bird is not drinking for some reason, then its not getting the med/wormer. Or another bird might be getting a lot of med/wormer. However, that being said, it's always worked that way for me.
