Every day, I get a lot of questions from my customers about whether they should have an algae eater in their aquarium or not. The majority of the time, they arrive at the store having been told to 'go get one a' them allergy eaters and it'll clear your tank right up'. They come in, point at a Hypostomus plecostomus or a Pterygoplichthys gibbiceps (common Pleco and Sailfin Pleco), and say 'I want one of them for my tank, I've got a big algae problem!'.
The typical course of conversation then flows through me asking them a number of questions that have nothing to do with the fish at all, and usually ends with them leaving the store with another type of algae eater, or nothing more than knowledge about how to combat their algae problem.
I will say this right now:
With few exceptions, no aquarium needs an algae eater.
There, now that the huge text is out of the way, let me clarify. With few exceptions, a well-maintained aquarium should not experience significant enough algal growth to warrant the purchase and maintenance of an algae-eating fish. Algae eaters are simply not the solution to algae in an aquarium; fixing the root cause of the algae is. If you knew that eating hamburgers gave you a common cold, you would stop eating hamburgers instead of constantly dosing yourself with Nyquil...wouldn't you?
Without turning this into an enormous thread on why algae occurs in the first place, let me just point out a few of the more common reasons; most of these are easily rectified by the home aquarist with little to no cost (and sometimes even a cost savings!).
- Turn your light off! If you do not have live plants in the aquarium, and you aren't at home to view your fish...your light should not be on. Your light benefits you far more than it does the fish in most cases. Turn it on for a few hours when you get home so you can view the fish and feed them, and turn it off when you go to bed. The majority of freshwater fish do absolutely fine with ambient light from the room (providing your aquarium isn't in a basement). Leaving your lights on for hours upon hours at a time is an invitation for algal growth.
- Keep up on your aquarium maintenance. This means your water partials and your filter changes. Water that's allowed to sit and accumulate nitrates will be much more likely to grow algae than water that has regular water partials done to it. Algae needs food to grow, and what it cannot make from the light it makes from the available fertilizer (nitrates) in your water.
- Consider changing your lightbulb. If you're using something like a SunGlo, or an equivalent light...change it out (assuming a lack of live plants in the aquarium). Light in the red spectrum is used by plants of all ilk in the production of green growth, which is all that algae is. Having a yellow/orange light over your tank is providing the perfect wavelength of light for algae to grow. Try to put something like a PowerGlo or other similar light over it; light in the blue/purple spectrum is used mainly for fruit/flower production, both of which algae lack. It will also bring out the colors in your fish.
- Test your source water. Sometimes, source water contains things that algae really likes, such as phosphates or iron. If you find that your source water has amounts of these things in it, you may want to consider using resins in your filter to remove them (expensive in the long-run), or using filtered water. Some LFS sell RO/DI water already made up, typically by the gallon, that is free of these things. Word of the wise, however: Do not, under any circumstances, use distilled water without treating it first. Distilled water contains none of the minerals a fish's body needs to properly osmoregulate. Using it in your aquarium will cause a slow and very painful death for your fish. If you wish to use distilled water, treat it with a product called R/O Right, made by Kent Marine. It comes in both a powdered and liquid form, and works well for re-mineralizing R/O and distilled water.
If you are having algae issues, please check those things before you run out to buy an algae eater. Adding a fish to your aquarium simply for utility is never a good thing to do; if a fish is in there that you may not have wanted much in the first place, you're less likely to properly care for it. And under no circumstances should you ever use algae-killing chemicals in your aquarium.
The impact such chemicals have on your water chemistry can be catastrophic in smaller aquariums, and when you think about all an algae killer does is give you a lot of dead algae decomposing in your aquarium. There are easier solutions available, so just avoid them altogether.
Now, on to the nitty gritty and species profiles!
Fancy Plecos of any type!
I'm sure you've been into your LFS and seen that beautiful Gold Nugget or Royal Pleco, and drooled over how gorgeous it looks. I totally agree! One of my favorite freshwater
fish is the Gold Nugget Pleco; I just think they're absolutely gorgeous. The problem lies in that the fancy varieties are only fair to middling at removing algae at best, and downright terrible at it at the worst. Clown and Royal Plecos, for example, enjoy rasping away at driftwood as the majority of their diet. They subsist on the small insects and algae growing inside it. You will very rarely find them eating algae off of your ornaments or glass.
Fancy Plecos can also be downright belligerent and territorial, even to the point of killing your fish. Leopard Plecos are especially vicious when deal with other fish in their territory, which is a shame because they're quite beautiful. In other words...leave fancy Plecos out of your aquarium unless you're keeping them as a species, and not as a living algae scraper.
Chinese Algae Eaters (Gyrinocheilus sp.)
Avoid these little monsters like the plague.
These are sold often as good algae eaters to unsuspecting aquarists, and while it's true that they do eat some algae when small and young, they very quickly give up the vegetarian lifestyle to pursue more carnivorous fare. It's not unheard of for these cretins to rasp the scales off the sides of larger fish, and they're just plain naughty regardless. Add their eventual size of almost a foot, and you have a fish that's unsuitable for a very large portion of the aquarists out there.
Common Pleco/Gibbiceps Pleco
(Hypostomus plecostomus/Pterygoplichthys gibbiceps)
I hesitated in adding these to the Not Recommended section, as they can do a rather good job of removing some types of algae. The problem comes from their eventual large size however, with both species reaching near two feet in length (as seen in the photo provided). These tank busters will outgrow your aquarium in short order, and there are far too many of them out there already in aquariums that are entirely too small for them. If you do not have a 75g+ aquarium...pass these giants up.
Good at Algae Removal
The Flying Fox is a small to medium-sized Cyprinid related closely to the Rainbow and Red-Tail Sharks. Maximum size is 4" or so, and with the exception of hair and some filamentous algae, they graze readily on all types. The main issue with this species is its territoriality; once it sets up shop around a clump of driftwood or an ornament, it can act belligerent towards tankmates that come too close; never keep two of these fish together in the same aquarium, as their aggression towards each other can border on the psychotic (much like their relatives the Red Tail Sharks).
Easily distinguished from the Siamese Algae Eater by the smooth edges of the black line running down its sides.
Better At Algae Removal
Otocinclus Cats (Otocinclus vestitus)
Oto Cats do a wonderful job of cleaning up algae, and have the added benefits of being non-aggressive and small in size. They best in small groups, and really do best in planted aquariums. They particularly shine in heavily-planted aquariums, cleaning the leaves of algae.
If you do not have plants in your aquarium, I would pass on Oto Cats.
Best At Algae Removal
Bristlenose Pleco (Ancistrus sp.)
Bristlenose Plecos are true oddballs, but wonderful algae eaters. They eat all forms of algae with gusto, and have an added bonus of being non-aggressive and attaining easily accommodated sizes. Plus, they're just plain cool looking! With a maximum size of around 4-5", they fit in most aquariums from 20g and up. While they do not harm plants directly, their grazing activity on the leaves of plants could potentially lead to broken stems, so care should be taken when putting them into planted aquariums.
Males are easily differentiated from females by the abundance of 'bristles' on their nose; females only have a small amount of short bristles on the front edge of their nose.
Siamese Algae Eaters (Crossocheilus siamensis)
Another cyprinid algae eater that closely resembles the aforementioned Flying Fox, the SAE is, in my opinion, the most versatile and efficient algae eater that can be put into your aquarium. They eat all types of algae, and with a maximum length of 4-5" and a slim body, it does not attain any great size. They do very well in planted aquariums, as they will not stress the stalks of plants if they alight upon them to graze. As with the Flying Fox, keep these fish singly to avoid aggression between individuals. Aggression and territoriality with other species of fish is very limited in this species, however they can certainly return it if harassed by other fish.
The SAE can be easily distinguished from the Flying Fox by the serrated edge to the black stripes running the length of its body.
I'd like to conclude this article by reiterating my initial point that almost no aquarium requires an algae eater to be successful and healthy. However, if you do choose include a species of algae eater in your aquarium, keep in mind that it will require attention and care like the rest of the fish in your aquarium.
All algae eater species benefit from additional feeding of algae wafers and fresh vegetables, and should be fed these 2-3 times a week. Zucchini strips make great fare; I keep a bag of them in my freezer at all times. The formation of ice crystals in the cells of the plant cause the texture to get soft, making them easier to eat. Frozen peas are a wonderful treat that are eagerly accepted by all algae eaters as well. Simply thaw them and squeeze them out of the skins. I've heard of people having great success feeding them pieces of melon, but this is a little too messy for my tastes. Most of them also benefit from a bit of animal matter in their diet. Sinking pellets/wafers work well, as do pieces of shrimp and clam. Plecostomus and related species do require some form of driftwood in their aquarium as well; they use the fiber for proper digestive health.
So in conclusion...if you feel the need to keep an algae eater in your aquarium, choose it wisely. Pick one for your specific application, and make sure you feed it as required, and fix the cause of your algae problem instead of putting on a living band-aid!