That Fish Blog – Aquarium Advice and Information

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

Hello, Frank Indiviglio here.

The African fan shrimp is not well established in the aquarium trade, but interest is growing.  I have maintained a group for approximately 2 years, and have found them to be fascinating, if a bit challenging in some respects.  Their mode of feeding is particularly interesting, but requires a bit of attention as to “presentation”…I’ll write more about that in Part II of this article.

NATURAL HISTORY

This shrimp inhabits rocky streams along the west coast of Africa, from Senegal to Gabon.  It is also recorded from the east coast of South America; however, the genus is not well studied and these populations may represent a different species.  Their natural history is not well-documented.

African fan shrimp are heavily-built and reach 4 inches in length.  The first 2 appendages are equipped with feathery bristles which are swept back and forth when the animal is feeding.  Most in the trade are tan to dark brown in color, but blue, yellow, pink and red specimens show up on occasion.

CAPTIVE HUSBANDRY

Captive Habitat

The Aquarium

A well-filtered 10 gallon aquarium will comfortably house 4-5 shrimp.  They seem quite social; I have keep 12 in a 55 gallon aquarium.  The tank should be well covered, in case they decide to explore by climbing filter tubes or heaters.

Heat and Light

I keep my fan shrimp at 76 F; their temperature range is reported to be 74-88F.

African fan shrimp only leave favored retreats at night, and then infrequently.

A Night Glo bulb  or similar bulb will allow you to view their nocturnal activities.

Substrate

A rock or gravel substrate is preferable, as such is what would be found in their native habitat.  However, people keeping these shrimp on sand report no problems.  They do not negotiate bare-bottomed tanks well, and seemed stressed by the effort.

Physical Environment – Habitat Type and Terrarium Decorations

African fan shrimp are very shy and retiring, and require suitable shelters if they are to thrive.  Mine seem quite specific in their choice of a retreat – once they settle in, they remain within the same cave or shelter, even if others are available.  I have observed several shrimp to occupy the same small caves for 18 months.

They will utilize rock caves or artificial structures and ornaments.  Despite their need for privacy, the shrimp seem unconcerned about being on view through glass…caves positioned near the aquarium’s glass will allow easy observations.  They prefer a “tight fit” over a spacious cave, and many will remain within one shelter, usually in physical contact with one another, if able.  I’m not sure if they prefer to live in groups (field studies are in short supply) or not, but they certainly do well when provided with a cave that allows them to congregate.

Water

Hailing as they do from fast-flowing streams, fan shrimp likely have high oxygen requirements, so be sure that your tank is adequately aerated.

They should be maintained at a pH of 6.5-7.4.  I use soft water, but this is not based on field research (in fact, water in rocky streams tends to be hard).

Like many invertebrates, fan shrimp are extremely sensitive to ammonia, and to copper and other chemicals that are found in fish medications.

I’ll finish up with feeding and  pass along a few observations next week.

We have much to learn about these and other fresh water shrimp… please write in with your questions and observations. Thanks, Frank Indiviglio.

A video of an African fan shrimp in the process of feeding is below: