Thomas wrote: << adding iron (which is quite natural in some habitats) seems to me nearly like > using peat to enhance water quality. But there is a difference: peat is for > health, iron is for good looking. Where is that line ? >> >> IMHO, a healthy fish will show its best colors, relevant to the ambiant conditions of light, color, etc. As it is currently believed, female Apistos tend to select mates, partially at least, based on color brightness. I suspect that if iron increases the intensity of certain coloration, then that is probably indicitive that said fish was iron deficient when the color was paler. If someone has evaluated the iron content of water in the A. nijsenni's native waters, it would be useful to use to confirm or deny this. Unfortunately, we generally only get hardness and pH from collectors, and then rarely. Bob Dixon