Hi. I will like to share my Killi experience of the last 3-4 years. Killis are just another type of fish which are not that hard to keep. They usually are not shy fish and will almost any food, but they benefit the most having high protein foods as they are carnivorous fish.
As stated in previous posts, first remember they like stability in their water. Any change in water will make them more "avid" to jump out of the tank. Remember this because when you buy them and put them in your tank they will feel the urge of getting out of there. Make sure you cover ALL possible holes on the cover, specially the one on the heater and on the filter (yeap, they will get out through there). Annuals are not as jumpy in my experience and from what Im told.
Killis can be good community tank residents. They keep to their own and tend not to be bullies. The Fundolopanchax species grow a bit more and their mouth is bigger, so they will try to eat smaller fish (lets say baby Cardinals/Neons or Small guppies). They will make their presence to be noticed but most of the time they are on the top of the tank minding their own business. If you get annuals Killis on the tank, they will behave except with their own. Males will kill each other even if they have no femles on the tank. Aphyosemion males can live together in community tanks in my experience.
Breeding Killis sometimes can be challenging. Breeding non annual Killis can be done in different ways. Some people like having bare floor tanks with floating mops, and then taking the eggs of the mops and raising thew babies apart. This requires more time checking the fish. I prefer the more "lazy" way, in which I have small pellets on the bottom on the tank just enough to cover the bottom. Also I have the mops, but I have the tank as full as possible with JavaMoss. The y leay eggs on all places and babies get born on their own and have many places to hide. I have been able to reproduce 3 species like this, all three which I have tried.
The annuals breeding is another story. They tend to lay eggs almost daily (this is true). Eggs need to get out of the water and need to remain on a damp place for months (some 3 months, others more depending on the species). For this reason, people left bare bottom tanks with some cannister half full with peat moss (yes, the same peat moss used for gardening). Annuals can start breeding as soon as the second day on your tank so bre ready when you buy them. One canister option is a butter plastic vase, in which you fill half with peat moss and cut and opening on the top big enough for them to get in. Once or twice a week you get the vase out, dry the peat moss by pressing it very hard on a piece of paper (newspapers are awesome for this, and dont be afraid to press them hard, eggs dont break I dont know how). After this dont even bother try finding the eggs as the are hard to see. Place the dry moss on zip locks, put the date on the bag, and store in the closet or a relative dry and dark place. After the required months, place the moss on water and a few hours later you will see the babies. If few or no babies comes out, you can dry the moss again and repeat the process a week later. Some people tell me ideally you should do this always and most times more babies will come out. This babies will eat fast and will grow fast. They show their colors in weeks, but will start fighting just as fast. Be aware of this as they will not tolerate each other for much time.
IMO all moderate experienced fish lovers should try this beautiful fish. People get scared about keeping them as they think they are expensive and hard to breed. But after a nice web search (specially on Aquabid
) you will see they can be found at reasonable prices and they are not as hard to keep as you might think. Ideally they should be paired on 5 or 10 gallon tanks (my pairs are on 10 gallon tanks) and some people think trios can work (never done trios, only pairs). Try them, you wont regret it. Hope this heps.