Join Date: Mar 2008
The following are a list of fish that are often suggested for algae control, but personally I believe they should be avoided for this reason. I strongly recommend you do not purchase these fish for the intent of algae control, but for the sake of being thorough I will describe them.
SAE: The true Siamese Algae Eater, C. Siamensis. When SAEs are young (6 months or less) they eat the hard stuff and work their way down, which is cool. They start out with string algae, BBA, and clado, and then start working on GSA and GDA once the other stuff disappears. SAEs are social fish and should be in groups no less than 3, but 5 is really a much better number. SAEs have SEVERAL large downsides. First off, they get big, really big, like 6+ inches...digest the last two sentences: they should be in groups of 5+ and grow to 6+ inches. In case you can't put it together, these fish need AT LEAST a 55g tank but really belong in a 75g+. On top of all that, after about 6 months, they stop eating algae, and instead turn to anything and everything else: shrimp, small fish, hairgrass, moss....anything and everything but algae. So now you've got a bunch of huge fish that don't eat algae, great. But wait, there's more! SAEs also become more and more territorial as they get older and they'll quickly turn on your other fish. In short, these are not the miracle fish you've been led to believe.
Florida Flag Fish: Florida Flag Fish(or the American Flag Fish) are also often touted as being great algae eaters. Like the SAE, they tend to work on the hard stuff first and work their way down. They are killies, so they'll breed pretty easily. However, like SAEs, if the algae supply gets low (and as they age) they start to munch on stringy plants (like hairgrass) and moss. Also like the SAE, they tend to become more and more aggressive/territorial as they get older/start breeding. People still mention this one from time to time as being a "good" algae eater, but I think most of the hobby has moved on from suggesting this one.
Plecos, of any kind: Plecos of any kind just aren't the best algae eaters. Most Plecos will eat your plants. Generally, the hobby knows this, but still suggest BN Plecos and Rubberlips. These fish do eat algae(and tend to leave plants alone), but it's really not their preferred source of food, so simply throwing them in your tank with only DW and algae to munch on isn't very nice of you. These fish are great, but should be kept because they are great, not because they are algae eaters(because, compared to the other fish on this list, they just aren't). There isn't really a big downside to BN and Rubberlips except, as stated, they aren't really great algae eaters. The other downside, and this is strictly a personal opinion, is that, even at 4", they are a bit too big and bulky for the planted tank, often disturbing plants. I don't have a lot of negatives for the fish, except, as I said, they just aren't "algae eaters".
Dishonorable Mentions: Chinese Algae Eaters are Not Algae Eaters, and they are majorly aggressive.
I feel like I'm leaving some off, so if I think of them, I'll add them.