Chromeaphysemion is an unreconized grouping of Aphyosemions that used to be comprised of the following species: bivittatum, riggenbachi, bitaeniatum, volcanum splendopleure, and loehnberghii. In the last 15 years quite a few more species have been described. It is pretty easy to tell the ones that belong to the grouping. Males have very large dorsal fins. Often magnificent colors. Females often are more colorful than other Aphy. species and many have a pair of horizontal stripes on their body. I took a look at the picture and its impossible for me to tell which location of volcanum it is. Most are found in the shadow of Mt Cameroon over volcanic soil. Guess why they are called volcanum! There are several color forms of volcanum available in the hobby and they show up on aqua*bid from time to time. They are well worth getting for a planted tank. I have a Chromeaphyosemion bitaeniatum in one of my planted tanks and I know in a short time I will have a flock of fry in the dense part of the plants.
Klaus