That looks like a guppy to me. I don't know why it owuld be in a canal drainage tube.
I doesn't look like a bass fry to me at all. It doesn't have enough fins to be a bass fry and even when they are small, bass fry are still pretty bass-shaped. I have caught bass that were literally under 2 inches and they were perfect bass, just in miniature.
How big is the fish? I assume it came from AZ?
Oh, ninja'ed! Yeah, mosquito fish sounds totally right.