One of the greatest joys of having a marine (and particularly a reef) aquarium is the opportunity to keep invertebrate animals. Not only do they bring a considerable about of visual diversity to the captive environment but can also play vital ecological functions. Perhaps some of the easiest of these creatures to maintain for extended periods of time are the marine arthropods. This group is enormous and varied. Even at the level of species, each member has its own specific requirements and habits. But, by and large, the shrimps are arguably the most amenable to typical community aquarium conditions, as their cousins (the crabs and lobsters) are too often unpredictably destructive.
Again, there surely are many exceptions to this. But the enduring popularity of the shrimps strongly attests to their general suitably for even the most delicate reef aquarium systems. Here we discuss just five of many such species that are attractive, easily kept and downright interesting for anyone to care for. With the very notable exception of the harlequin shrimp, all of these species can be fed just about any kind of prepared or frozen aquarium fish food.
1. Cleaner (or skunk) shrimp (Lysmata amboinesis)
This ever popular shrimp is well known even to beginner marine aquarists. That notwithstanding, there are important considerations to make before including it in your aquarium community.
Its common name is derived from its habit of feeding on fish ectoparasites. Some say that it also feeds on dead tissues. The fish seem to appreciate this activity very much and may even compete for their place at cleaning stations. However, there is very little evidence that the cleaner shrimp is effective at controlling or even impacting the most devastating and commonplace fish parasites (e.g. marine ich). Moreover, this shrimp cannot be safely housed with many predatory fishes such as groupers, lionfish or triggerfish, which seem to like the shrimp’s flavor far more than its services.
Another problem is usually encountered when attempting to keep this species in groups. One thing that is cool about the cleaner shrimp is its readiness to form pairs; what is not so cool is their well-documented jealousy. Once a pair is formed, they seek out and kill all others of the same species to protect the mate and the territory. Thus, they are best kept as pairs or individuals with only small, nonpredatory fish species. They occur throughout the tropical Indo-Pacific Ocean and the Red Sea.
2. Harlequin shrimp (Hymenocera picta)
This strange and beautiful creature is frequently encountered in aquarium shops. However, their exotic appearance is matched by an equally exotic diet. This species doesn’t just eat starfish, it only eats starfish. This not only excludes it from many marine aquaria (which typically do include at least one species of sea star), but can make it very difficult and costly to feed. As such, it is perhaps best housed in a species tank. Kept in this manner it is relatively easy for the aquarist to drop in the occasional (somewhat) inexpensive starfish (e.g. linkia or sand-sifting starfish). Unwelcome (albeit handy) explosions of pest species such as Asterina stars may also be a good source of food for the harlequin shrimp. As they are extremely territorial, one should acquire them singly or in mated pairs only. They occur in much of the tropical Pacific Ocean.
3. Banded coral shrimp (Stenopus hispidus)
The banded coral shrimp has been a staple of the marine aquarium hobby for quite some time now. It has proven to be a very hardy and adaptable animal in captivity. If anything, it’s only drawback can be that it is maybe a little too tough. This species can be very aggressive. Unless obtained as a mated pair, there is a good chance that multiple individuals will fight to the death. There likewise is a risk of the shrimp attacking and killing smaller, slower bottom-dwelling species such as dragonets. To a lesser degree than the cleaner shrimp, this species is also known to feed on fish parasites. It occurs throughout the tropical Atlantic Ocean.
4. Anemone shrimp (Periclimenes pedersoni)
This beautiful, even dainty, shrimp is best known and loved for its symbiotic association with sea anemones (usually Batholomea annulata). This species has been observed to be a feeder of fish parasites, but seems to be content to spend most of its time hiding within the safety of its host’s tentacles. The related Yucatan anemone shrimp is very similar in life style, though it prefers the anemone Condylactis gigantea. These little shrimps are great for smaller reef systems, provided that they are properly set up and stocked for the anemones as well as for the shrimp. Both of these species occur in the tropical West Atlantic Ocean.
5. Pistol shrimp (Family Alpheidae)
This neat little crustacean has an enlarged claw that, when snapped shut, can cause a shock wave capable of stunning enemies and small prey. Some claim that they are able to break glass aquaria, though this certainly doesn’t appear to be a common occurrence. Even so, the clicking can be very audible from outside of the tank and can no doubt cause at least a little concern to the keeper.
Perhaps their advanced weaponry is compensation for their reputedly poor eyesight. This burrower spends much of its time hiding in the dark, within (sometimes elaborate) burrows of its own making. To the delight of many fish keepers, these industrious little shrimps form a fascinating relationship with a certain group of gobies, the aptly named shrimp gobies. These gobies take up residence in the burrow and help to defend it. Acting mainly as sentries, some of these gobies have been given common names such as watchman goby.
The most important consideration for those keeping pistol shrimps is to provide an adequate substrate. These soft-bottom dwellers prefer a mix of mainly finer materials such as sand with a little bit of courser materials such as gravel and smallish rubble. Members of this family can be found worldwide in both tropical and temperate shallow waters.