Hello, Frank Indiviglio here. Please see Part I of this article for further information.
Feeding
The fan shrimp’s unique mode of feeding is very interesting to observe. The first 2 appendages are lined with plume-like bristles which are waved about when food is detected. Tiny organisms, organic detritus and algae are trapped in these and transferred to the mouth. Fan shrimp will also pick food particles from the substrate, in more “typical shrimp” fashion, and I have several times observed them feeding on dead fish (at night).
If you keep fan shrimp with fish, it is important to introduce food at night, just before you turn out the lights…the shrimp will rarely get enough to eat otherwise. I keep a few yo-yo loaches, Kuhli loaches and armored cats with mine, but beware of adding too many nocturnally-feeding fish.
Unlike many shrimps with specialized feeding adaptations, these accept nearly any pelleted or freeze dried food. One of the few published reports on their feeding habits in the wild (please see below) established that fan shrimp are omnivorous, with algae forming a major part of the diet. I therefore provide my shrimp with both plant and animal foods. I use algae and shrimp tablets as a basis of the diet, alternated with flake and freeze dried foods. Liquid invertebrate food may also be squirted into their hiding places.
African fan shrimp begin waving their feeding appendages about as soon as food is sensed. I usually drop algae tabs or other foods right near them, after which they will move over it and begin waving away. If you look closely, you’ll be able to see fine particles of food lodge in the brushes as the tablet dissolves.
My fan shrimp do not gravitate towards the filter outflow in order to trap food, as do the Singapore wood shrimp (Atyopsis moluccensis) which share their tank. They will, however, filter fine food particles from whatever water currents pass by their lairs. Some suggest keeping these shrimp in well-established tanks that house high populations of diatoms and other micro-organisms. Certainly this is a good idea, but as we know little of their actual food intake needs, I would suggest that shrimp in these situations be fed as described above as well.
Social Grouping/Compatible Species
African fan shrimp do exceedingly well in same-species groups; I have also kept them with Singapore wood shrimp, Atyopsis moluccensis, Japanese marsh shrimp, Caridina japonica and cherry shrimp, Neocardina denticulate. Small, peaceful community fish such as guppies, zebra danios, cherry barbs and so on are also fine, but please see the feeding cautions above.
Alternatively, you can house fan shrimp with fish that do not compete for food, i.e. live food specialists such as elephant-nosed morymids and butterfly fish (both of which are also native to West Africa, although not to the same habitat-types).
Small and large cichlids, carnivorous catfish and crayfish will attack fan shrimp.
Captive Longevity
Unpublished reports set captive longevity at just over 5 years.
Breeding
Anecdotal reports claim breeding success in heavily-planted outdoor ponds. The young are said to be planktonic for a period of 2-3 weeks after hatching, which would certainly complicate matters in an aquarium. I plan to look into this further and report back.
Miscellaneous
Fan shrimp are, as mentioned, very much oriented to a specific home cave, being more like crayfish than shrimp in this regard. I imagine (but this has not been established) that such holds true in the wild as well. I have observed them to become quite stressed if routed from their retreats. In most cases, they wander about, often for days, before returning to the cave.
Be extremely careful when working around them, and avoid moving or re-arranging their caves. I usually forego cleaning the glass directly in front of their caves, unless I happen to catch the shrimp “away from home” on rare foraging forays. In those cases I’m always careful to return the rocks to their original position – a slight change in their shelter’s height or depth has seemingly caused my shrimp to seek “new accommodations”.
We have a great deal to learn about this and other freshwater invertebrates… please write in with your questions and comments. Thanks, Frank Indiviglio.
Very little has been published about this species in its natural habitat. An interesting article concerning field research with fan shrimp in Nigeria is posted at:
http://www.wajae.org/papers/paper_vol13/Food_and_Feeding_Habits_of_Atya_gabonensis_from_Lower_River_Benue_in_Northern_Nigeria_full.pdf