Kribensis (Pelvicachromis pulcher) become pale upon transfer into a breeding tank
I kept and bred Kribensis in my 180 liter aquarium. After they had cared for their fry for about 5 weeks I have put them into a smaller tank for spawning again. Strangely, they have become considerably paler since then. Is it maybe too bright for them?
this is one of several possibilities, but there may also be other reasons (e.g. unsuitable water parameters, insufficient space, unsuitable setup, transfer stress etc.). These factors should be checked accordingly. I generally tend to let brood-caring fish spawn in their home aquarium, and then catch the juveniles when the time has come to do so, even if this reduces the "yield" - the stress is in any case considerably lower for the parents.
Dr. Bodo Schnell