Originally in: http://www.wetwebmedia.com/ca/WWMDigitalMagV1Ish1.htm, Related FAQs: Marine Scavengers 1, Marine Scavengers 2,  Marine Scavengers 3, Sifter Gobies,  Marine Algae Eaters,  Hermit Crabs, & FAQs on Scavenger: Rationale, Compatibility, Species/Specimen Selection, Clean Up "Crews", Worms As  Scavengers, Snail Scavengers, Shrimp Scavengers, Hermit Scavengers, Crab Scavengers, Cucumber Scavengers, Sea Urchin Scavengers, Serpent Star Scavengers, Seastar Scavengers, Fish/Groups as Scavengers, Losses/Troubleshooting, Related Articles: Scavengers/Clean-up Crews for Marine Aquariums, by Bob Fenner, Marine Maintenance, Algae Control, Sand Sifters, Snails, Hermit Crabs, Sea Cucumbers, Shrimp Gobies, Genus Valenciennea Gobies, Hermit Crabs, Nutrient Control and Export,  Originally run in: http://www.wetwebmedia.com/ca/WWMDigitalMagV1Ish1.htm  Some Fishes Are Good For More Than Just Looking At

By James W. Fatherree, M.Sc.

The lawnmower blenny (Salarias fasciatus) is an all-time favorite, as they are great algae eaters with funny personalities

Hobbyists that keep marine aquariums have a great number of fishes to choose from when it comes times to stock a tank, with many, many dozens, if not hundreds of species available. The vast majority of such fishes added to folks aquariums will be picked due primarily to their good looks, and possibly due to some type of interesting behavior they exhibit. However, there are numerous fishes that should be given a spot on an aquarists stocking list for the jobs they can perform in a tank.

There are quite a few attractive and/or interesting fishes that will do some sort of desirable work for you, thus they can offer an added bonus when selected. For the most part, Im speaking of algae eating fishes that help the glass, rocks, and such cleaned up, but there are others, too. These are fish cleaning fishes and the sand/gravel cleaning fishes, so lets take a look at some good algae eaters, fish cleaners, and substrate cleaners.

 

The Fish Cleaning Fishes:

Sometimes, even the fishes in an aquarium can benefit from a good cleaning, which can be taken care of by a number of relatively small fishes that specialize in cleaning other fishes. There are numerous types of such cleaners that will nip and pick tiny parasites, dead skin, scales, mucus, and such off other fishes, getting themselves a meal in the process. Of course, the fish being cleaned also benefits from this, as they get a good going over that they cant do for themselves.

The cleaning species are recognized by other types of fishes for what they are. So, fishes that wish to be picked clean will allow a cleaner fish to browse over their bodies, and will typically let them stick their head, or even swim, right up inside their mouths and inside their gill openings in order to do a thorough job. The cleaner doesnt have to worry about being eaten (except in rare cases), and will gladly go right to work inside and out. Note that fish parasites are particularly common and problematic on their gills, rather than on the outside of their bodies, so cleaner fishes may spend quite a bit of time working over the gills, more so than the body.

These cleanings obviously have their benefits, and eager fishes will often gather and line up around a known "cleaning station", waiting for their turn where one or more cleaner fishes hangs out. This relationship between cleaners and cleanees persists in aquariums, too, so adding a cleaner can help keep all the fishes in a tank in their best health. However, its likely that the most common cleaner fishes you'll see for sale are the cleaner wrasses (Labroides spp., usually dimidiatus), which happen to be the worst choices for your aquarium.

These wrasses are great at cleaning, but it is very unusual for them to learn to eat any sorts of fish foods that you might provide. They simple dont like fish food, as best as I can tell. This definitely a problem because in the wild (or in very large public aquariums and such) they have lots of big fishes to go over in any given day and can find plenty of food, but in a typical home aquarium there won't be enough cleanees to provide a cleaner wrasse with a steady supply of grub. So, they typically wither away slowly and eventually die of starvation no matter how much food you might give the other fishes in your aquarium. And on top of that, the removal of these fishes from their natural environment has been noted to affect the health of the cleaner-less fishes left behind.

Cleaner wrasses, like Labroides dimidiatus, will eagerly work on larger fishes, often giving their gills a good going-over. As you can see, many fishes will line up for such services. However, these wrasses typically will not eat aquarium foods and often end up starving to death in tanks.

Still, you shouldnt give up though, as neon gobies (Gobiosoma oceanops), sharknose gobies (G. evelynae), and yellow-line gobies (Elacatinus figaro) are good cleaners, too. They aren't as big or active as the wrasses, and don't have the colors that many wrasses have either, but they'll eat fish foods. In fact, they'll eat a lot of different foods, and can even be kept in aquariums with no other fish to clean at all. So, you dont have to worry about them starving to death, which makes them a much better choice than a wrasse. And, to ease your mind, aquacultured cleaner gobies are available, which means theres no negative effect on the reefs if you bring one of these captive bred specimens home.

The sharknose goby (Gobiosoma evelynae) is a small, but good cleaner fish that will also eat many aquarium fish foods.

Even though this article is about fishes, I guess I should also throw in the fact that there is a variety of shrimps that can make great cleaners, as well. So, if a cleaner goby isn't what you're really looking for, keep an eye out for a good shrimp and please leave the wrasses alone!

The Substrate Cleaning Fishes:
If you have a reef tank with a deep bed of fine sand, youll want to keep the bed well stocked with all sorts of substrate-dwelling invertebrate critters to help keep it from becoming choked with detritus. Thus, you don't want anything in your tank that makes its living by eating small sand-dwelling invertebrates, or that has a habit of stirring things up too much, too often. However, if you have only a thin layer of sand or fine gravel for decorative purposes and want to keep it clean(er), there are a few fish helpers you can employ to do that, too.

There are several substrate-sifting species available, with the yellowhead sleeper goby (Valenciennea strigata), the sixspot sleeper goby (V. sexguttata), and the dragon goby (Amblygobius phalaena) being three examples. Like other sifters, these will move around the bottom of a tank and scoop up mouthfuls of sand/fine gravel looking for tiny bits of food. This provides them with meals and also helps to keep the substrate clean in the process. They churn the bits around in their mouths, after which they drop from the fishes' gill openings, minus anything the fish considers edible.

The sixspot sleeper goby (Valenciennea sexguttata) is a great sifter, that will help keep the substrate cleaned up as long as the grains arent too big.

Their activity keeps the substrate stirred up well, breaks up detritus, and also keeps algal growth down. This keeps the substrate cleaner looking, and also puts detrital particles into suspension where they can be collected by mechanical filters if you use them. There may also be an added benefit to any filter-feeding organisms present in the tank, which can make use of the fine detrital particles and various tiny organisms that may be freed from substrate by the fishes' activities.

Fortunately, these fishes will typically (but not always) learn to eat other fish foods that are offered, and thus won't starve if they can't get what they need from your bottom cover. However, you do need to keep in mind that these fishes can't handle medium to large gravel sizes. Thus, they should only be kept in tanks with appropriate substrates if you want to see them do what they do naturally and expect any work out of them. Also note that while they stay relatively small and some may do fine in mated pairs, most of them tend to not get along with other bottom-dwelling fishes.

The Algae Cleaning Fishes:
Nuisance algae can be much more than just an eyesore to a reefkeeper, as it can be deadly, too. algae can cover the sides of a tank with a green haze, can overgrow sand and rocks, and can even smother corals, sponges, and such living on these substrates. It can also be a real pain to scrub away and clean up if it gets out of hand. Therefore, it makes good sense to choose some fishes that will eat unwanted algae and earn their keep to some degree in your aquarium. There are plenty to choose from, so lets finish up by taking a look at some of the common types that can help.

The first type of algae-eating fish that typically comes to mind is a tang (also called a surgeonfish, depending on who you ask). There are many types of tangs, and theyre available essentially everywhere you look for good reason. Most all of them are colorful and attractive fishes with some personality, and theyre good algae-eaters, too. Various tangs will spend their entire day roaming around non-stop, pecking and nipping at fine algae that can form a coating on rocks and such, and larger macroalgae that sprouts up and into the water, as well. In general, theyre all invertebrate safe, as well, and wont bother your other critters. There are exceptions, but theyre few and far between.

The downside for some is that many species arent very good at removing algae from glass or sand. Most have small snout-like mouths that are good for nibbling, but there are a few others, like the Kole tang (Ctenochaetus strigosus), that have a better mouth for working on glass and such. So, some tangs are better for cleaning up some particular kinds of algae and surfaces than others. Unfortunately, there are often some compatibility and size issues to deal with too, but if youll do a little research you should be able to find something suitable.

The Kole, or yellow-eye, tang (Ctenochaetus strigosus) is one of the few common tangs that are really good at cleaning smooth surfaces like glass. Their mouths are well-designed for the job.

While they arent as popular in the hobby, the Rabbitfishes (some of which are called Foxfaces) are certainly good at removing unwanted algae, too. These fishes are typically very hardy and will also pick and nibble away at all sorts of algae. And like the tangs, these will generally leave your critters alone unless they are underfed. Ive found that they arent as picky about what they eat as some tangs can be, but again, there can be some size/compatibility issues with various species. Thus, youll need to do some checking before bringing one of these home, too. You also need to be careful with them if you ever need to handle one for some reason, as these are some of the few sorts of fishes that possess venomous spines. Fortunately, theyre not aggressive though, and wont come after you with their spines. Theyre for defense.

Rabbitfishes, like this Onespot Foxface (Siganus unimaculatus), can be effective and attractive algae eaters. But, you need to be a little careful, as they are also poisonous.

Next, there are the angelfishes. Larger angelfish species are typically unsuitable for life in reef aquariums, as their diets often include sponges, corals, and other invertebrates - and they can get really big, too. However, the smaller angelfish species (typically called pygmy or dwarf angels) are much more likely to stay out of trouble and do some work in the tank, too. Most of these belong to the genus Centropyge, come in lots of gorgeous colors and patterns, and also stay under 6 inches.

However, pygmy angelfishes arent as desirable as the other fishes covered, because they typically just dont go after algae they way tangs and Rabbitfishes do. But, they will typically help out at least a little. Still, as is often the case, there are some compatibility problems with them at times, as they often dont get along with various other fishes. And, while they usually are completely invertebrate-safe, there are individuals that may decide to pester or nibble at various invertebrates like giant clams and some corals, too.

Lastly, there are a quite a few popular bottom-dwelling, algae-eating blennies. Good examples of these are the Bicolored blenny (Ecsenius bicolor), the red-lipped blenny (Ophioblennius atlanticus), and the lawnmower blenny (Salarias fasciatus), all of which will work over various surfaces in a tank. These have big mouths and are particularly good at cleaning glass and other smoother surfaces, too, which is a plus since many other types of fishes arent as good at cleaning smooth surfaces. Usually it looks sort of like they are head-butting the substrate or glass when they eat, so they are kind of fun to watch, too. But, again, there can be compatibility issues with them, as none of these are likely to get along with each other, or other individuals of the same species. So, one per tank is often the way to go. Additionally, some are also known to nip at various corals and giant clams at times, although most wont bother anything.

And thats about it. There are certainly other types of fishes that will do some work in a tank, but these are some good examples of readily available types that will do a job for you. So, do a little thinking and some homework, make some appropriate choices, and enjoy having some good fishes that are good for more than just looking at.

Good sources for more information:
FishBase Global Information System: www.fishbase.org/home.htm

WetWebMedia: www.wetwebmedia.com

Michael, S.W. 2001. Marine Fishes: 500+ essential-to-know aquarium species. T.F.H. Publications, Neptune, NJ. 447 pp.