I'll delve into the wonderful world of shrimp
, then get some info together on stars and urchins. BTW, urchins actually help to spore out the coralline algae, so in essence, it helps it to spread.
Let's start off with cleaner shrimp. There are a variety of different types, the most common being Skunk Cleaner, Blood Shrimp, Coral Banded Shrimp, and the Peppermint Shrimp (clean tank of aiptasia). These critters clean a variety of fish species, and set-up little cleaning stations in crevices and caves waiting for a fish to come in. They attract fish by waving their antennae about, or rocking back and forth. As the fish gets closer, the shrimp dance a little more, and will stroke the fish with the antennae as it gets closer. When the fish stops by, it may pose a certain way. Such as, raising up its gill cover (closest to the shrimp), raising up its fin, or opening up its mouth nice and wide. I've noticed in my own tank these different postures, and the shrimp hops aboard and goes to town picking at the fish.
Here's where the controversy comes into play. Do the shrimp really clean the fish? According to Scott Michael in an article on
Coral Realm:
It has long been assumed that these crustaceans ingest parasites and dead tissue. However, there is little information in the scientific literature that actually confirms that they eat parasites. There is one study that demonstrated that Pederson's cleaner shrimp (P. pedersoni) removed juvenile cymothoid isopods from fish hosts. (These researchers did not observe Periclimenes grabhami, Stenopus hispidus, and S. scutellatus removing any parasites, although anecdotal observations suggest that they do.) Cleaner shrimps will also "graze" on the fish's body slime and may ingest bits of fin. The shrimp will pick at the fish's body surface, under the gill covers and in the mouth. The client seems to "enjoy" the tactile stimulation provided by strokes of the antennae and antennules. This reinforces the posing behavior of the client.
Lysmata amboinensis (aka Skunk/White-Striped(L. gabbami)/Eel/Scarlet/Ambon/Humpback/Redline Cleaner Shrimp), are cool shrimp. They tend to be more "outgoing" in comparison to the Blood Shrimp, IMO. You can keep more than one to an aquarium, and will likely get them breeding (they are hermaphroditic). Larvae rearing is another topic all together, and is difficult considering the size of these larvae after hatching. Just consider the larvae to be a tasty treat for those inhabitants that take advantage of it. One thing I read about was the shrimp may lose their desire to clean fish after being in the captive environment over time. I've noticed the opposite in my tank.....the fish have lost interest, while the shrimp are doing everything in their power to get a prospective client. They wave their antennae like mad, and if a fish happens to slow down, they try desperatly to hop on, only to have the fish get away as fast as it can. I think the Anthias are the only fish giving them the time of day anymore. It is suggested the shrimps lack of interest stems from the availability of food in the aquarium....left over food bits are quickly snatched up by the skunk cleaners. If they don't get it as it floats past, then after lights out, the shrimp are likely on the hunt for any left overs. I'm not sure as to why my fish have lost interest in them. One last comment. Anthony Calfo mentions in his Reef Invertebrates book, and I also read an article by Nathan Cope linked below, which talks about these shrimp and Tridacnid clams....some have nipped and harassed them.
Shrimp for the Tropical Marine Aquarium Hobby
A word of warning, Lysmata have been known to wade into corals and tear them open to get at recently ingested food. Personally, I haven't experienced this, but I imagine this sort of thing would only occur if the shrimp were not being fed sufficiently. I saw an interesting post on the "reefs" newsgroup recently telling a story about a Redline sitting on a tridacnid clam and tearing at it's mantle. The clam apparently withdrew it's mantle but did not close its valves (shells). The owner of this nefarious shrimp wanted it to cease immediately, so gave it some food. After finishing the food, the shrimp climbed back onto the clam but by this time, the clams mantle was withdrawn well down into the animal, despite the valves still being open. The shrimp was not discouraged; it climbed into the clam whereupon it promptly closed, killing the crustacean.
Lysmata debelius (aka Blood/Fire/Cardinal Shrimp). Same as the Skunk cleaners, only they tend to be more on the shy side. It is also noted that they don't clean as eagerly as the skunks. Beautiful shrimp, with the deep red color carapace, with white spots, and the white antennae.
Stenopus hispidus (aka Coral Banded Shrimp/Banded Coral Shrimp). This species doesn't clean as well as others, but has been known to occasionally clean moray eels in the wild. If anyone has actually seen their Banded Coral Shrimp clean, please post about it. I would love to hear an account. These shrimp should be kept only one per tank (and without other shrimp), unless in a huge environment, where the shrimp can avoid each other, or bought as a pair. Be certain to feed the shrimp a piece of meaty fare, prior to feeding corals or anemones in the tank. This will help to avoid the shrimp stealing the food from the other invert. Quote from same article linked above:
Banded Coral shrimp are known to clean fish in the wild but they tend to be large fish and the cleaning is usually performed while the fish is asleep. In the captive environment, they don't seem to be very interested in their doctor's duties. I do volunteer work at the local public aquarium and in the evening when the tank lights are off but the room lights still on, I've seen a Banded Coral shrimp on its nightly "inspection", wandering around the aquarium with large angels following, trying to "persuade" it to clean them. In the home aquarium, these shrimp are also known to "misinterpret" their cleaning duties and go around the tank "tidying up" by eating small fish! I once had a sick Mandarin Dragonet that swam past a Banded Coral shrimp and it was grabbed with one of the large chelae and held. I intervened, so I don't know what would have happened but I do know that small gobies that I have bought have tended to disappear when I have kept Coral Banded shrimp. Stenopus do not usually behave very harmoniously with other shrimp, either. It's been reported that they will kill Lysmata.
The last shrimp I'll mention is Lysmata wurdemanni (aka Peppermint Shrimp). This shrimp is often employed as clean-up to Aiptasia problems. I know the ones I introduced to the aquarium didn't take long to get rid of the menace anemone. However, it came at a cost....my favorite zoo colony was eaten by these guys. I sat in horror one evening after lights out, watching them destroy my zoos (this was after the aiptasia were wiped out). I only have one left, and have yet to see an aiptasia show its face again, and no other corals have been disturbed by it. The peppermint shrimp in my tank, can be found only at night when it ventures out of its hiding spot. One thing to keep in mind when shopping for peppermint shrimp. Sometimes shrimp from the genus Rhynchocinetes ("movable beak") Hinge-beak/Camel shrimp, are sold as peppermint shrimp. These shrimp will not control pest Aiptasia anemones like "true" peppermint shrimp, according to Anthony Calfo in his Reef Invertebrates book. Here is another link regarding the differences between the two peppermints
Identifying Peppermint Shrimp, Lysmata wurdemanni. This article, however, contradicts what Anthony Calfo claims, and says the Camel shrimp do eat aiptasia. I'm pretty confident that my shrimp is a true peppermint shrimp. It has a very short rostrum. I've also witnessed my peppermint shrimp steal food from the RBTA I had in my tank.
So there you have it....
.....I know, short and to the point, right? lolol. No matter which shrimp you pick out, it will likely scavenge on scraps of left over food, and provide you with entertainment (whether it is observing them clean, or letting them clean your hand).
