Joe, via email
I want to be able to keep a number of cleaner shrimp in my 75-gallon reef
tank, but my dealer says they will fight. Are there any species of shrimp
that can be kept together?
With plenty of cover and conscientious feeding, cleaner shrimp can be kept more than one to a tank; though all shrimps identified as cleaners will consume one another to a degree, given a lack of alternate food or cover. Of the five species in three families of cleaner shrimp most often available to aquarists (there are others) (Periclimenes, Lysmata, and a Stenopus; all with long white antennae); the only ones I'd personally try in more than a "pair" (best as a male and female) are L. amboinensis and L. grabhami in a 75 gallon system.
In my opinion, the small Periclimenes are best left in the sea due to their strong association with hard-to-keep anemones. Should you not be dissuaded, do study up and arrange a biotopic presentation with these shrimp... along with their symbiont anemones.
Should you have big bucks and the stomach for your livestock possibly consuming each other, Lysmata shrimps can be crowded together. The scarlet shrimps, L. amboinensis from the Indo-Pacific and L. grabhami from the Caribbean, and the blood shrimp, L. debelius, are often jammed together en masse at wholesalers. The former two are hardier and less expensive.
Of the boxer shrimps, the Coral Banded Stenopus hispidus is a standard in the trade/hobby; but quite territorial. In a tank of your size, any other than a matched pair will seek out others for snacking. These are best purchased as a "mated pair", ideally being housed together as such at your dealers. Ditto for other boxer shrimp species.
Know also that these shrimp may "sample" your live corals as well as each other, that they cannot live on just what they "clean" from their fishy tank-mates, and that they won't necessarily clean anybody (they're picky about being "picky").
BTW, for coldwater marine aquarists, there is occasionally offered a sixth cleaner species hailing from California (Lysmata (Hippolysmata) californica); often photographed in association with our endemic moray eel (Gymnothorax mordax).
All Cleaner Shrimp species prefer subdued lighting, plenty of rocky cover, nooks and crannies, molt every 3-8 weeks normally, consume most all foods in addition to cleaning, and are sensitive to fast changes in water chemistry, particularly salinity... New synthetic water should be pre-made, stored for a week and matched to their systems specific gravity. There are actually a few families of crustaceans referred to, and containing fish-cleaning species. The more popular, readily available are linked below:
Family Palaemonidae, two subfamilies: Pontiinae: Commensal, Anemone Shrimp, Rock Shrimp,
Family Stenopodidae , Boxing Shrimp. First three pair of walking legs with pinchers, the third large. Use long, white antennae to "advertise" their cleaning services. Usually found in pairs (female larger) in a permanent cleaning station.
Further Reading on Cleaner Shrimp:
Raising Peppermint Shrimp: www.lysmatapublishing.com
Baensch, Hans & Helmut Debelius. 1994. Marine Atlas, v.1. MERGUS, Germany. 1215pp.
Brach, Vince. 2001. The cleaner scene. FAMA 1/01.
Clemens, Ronald C. 1979. Pederson's cleaner shrimp, Periclimenes pedersoni. TFH 6/79.
Debelius, Helmut. 1985. Cleaner shrimps of the genus Lysmata. FAMA 7/85.
Delbeek, Charles. 1987. Cleaner Shrimps (Genus Lysmata) for the home aquarium. ATOLL 1:2, 87.
Ellis, Gerald R. 1985. Cleaner shrimp. FAMA 10/85.
Jonasson, M.1987. Fish cleaning behavior of shrimp. J. Zool. v. 213, no. 1, pp 117-131; 1987.
Mayland, Hans J. 1973. The whitebanded cleaning shrimp. Marine Aquarist 4(1):73.
Peters, Michael J. & Joyce Wilkerson. 1996. Scarlet cleaner shrimp larval development. FAMA 3/96.
Walls, Jerry G. 1983. Two colorful shrimp of the genus Lysmata. TFH 7/83.
Wilkerson, Joyce D. 1994. Scarlet cleaner shrimp. FAMA 8/94