does anyone do anything specific when they add new cichlids? i dont have much luck when i add to my stock..
The general answer to this question is that when stocking mbuna's it's best to do it all at once or within a short time frame (all in the same day if possible, but definately within 2 weeks from 1st fish to last fish added).
As the existing mbuna's in the tank become established it will become challenging to add new ones (due to the territorial nature of these types of fish, new additions will be viewed as and treated as intruders, as you have witnessed).
If doing the above is not possible, the next best thing is to add new mbuna's in groups (4+ at a time, preferably of the same species to avoid singling out by the established mbuna's).
The exception to this is if the new mbuna's are larger and more aggressive than the established fish. For example adding a single large 5.5" male red zebra into a mbuna set up stocked with 2.5" juvies won't be a problem for the male zebra. Adding this same fish in a tank containing one or more 5.5" male red zebra's may result in immediate aggression.
Other successful techniques include adding smaller juveniles (which aren't usually seen as a threat) or adding them at night. Also it's usually best to add the aggressive species last. Adding mildly aggressive or even aggressive species in a tank that contains highly aggressive species will be challenging.
In large tanks with large groups of fish it's easier to add new fish in ones' or two's. For example a 125gal with 30 mbuna's including 10 yellow labs, one could probably add a single female yellow lab seamlessly.
In regards to the success that you had with the previous cichlids you had in this tank, how large were they and how long did they exist in the tank?
In my experience, mbuna aggression doesn't really peak until the fish are about 4 years old, or when they reach full grown size (usually 5"-6" for most species, though some are larger or smaller than this).
