Fish was the chaplain for the Fourth Kansas Volunteer regiment. The Adjutant General's report shows he enlisted August 16, 1861 and was mustered in September 4, 1861. He was one of the three chaplains of Lane's Brigade who were detailed in mid November 1861 to take charge of the Black refugee train the Brigade had accumulated on its march from Springfield back to Fort Scott, with the instructions to find homes in Kansas for them. I believe you can find on the internet an excerpt from chaplain Hugh Fisher's "The gun and the Gospel" which mentions this.

The fourth Kansas was combined with the Third in the spring of 1862 and this became the Tenth Kansas. The records for the Tenth will give the original muster date but fail to mention prior service in the Third or Fourth regiments.

Chaplains were officers, but I am ignorant as to what rank they held.