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FAQs on Freshwater Blue Green Algae (BGA) & Their Control

Related Articles: Algae Control in Freshwater Aquariums by Bob Fenner, Dealing With Algae in Freshwater Aquaria by Neale Monks, (some) Algae (in moderation) Can Be Your Friend, ppt presentation, Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, by Bob Fenner, Algae Eaters, Otocinclus, Loricariids, Siamese Algae Eaters/Crossocheilus,

Related FAQs: Freshwater Algae 1, Freshwater Algae Identification, FW Algicides, Algae Eaters, Aquarium Maintenance, Freshwater Aquarium Water Quality, Treating Tap Water for Aquarium Use, pH, Alkalinity, Acidity, Freshwater Algae Control, Algae Control, Foods, Feeding, Aquatic Nutrition, Disease,

BGA comes in many colors... green, black, red, gray...

Cyanobacteria that is not blue-green in freshwater tank    4/4/17
Hello WWM Crew:
<Howsit Trace?>
Greetings from Canada! There is something growing on my Rotala and l am not sure what it is (picture attached). It looks like cyanobacteria, but it's not blue-green.
<Mmm; BGA comes in many colors... black, brown, reds...>
Also, I haven't noticed the telltale smell. Do you think that is what it is?
Many thanks,
<Not w/o microscopic exam at least, and maybe some simple chemical testing (for reserve foods). I have a small book on aquatic algae, which is parsed about on WWM... or you can/could avail yourself of the Net. Again; simple
to discern by looking under magnification. No nucleus, a single strand of circular DNA.... Bob Fenner>

Re: Cyanobacteria that is not blue-green in freshwater tank    4/4/17
Thanks Bob! I didn't expect such a quick response as I thought it was the wee hours where you are.
<Back in S. Cal. Tracey>
As for magnification, you must have quite the microscope. I would have thought I needed an electron microscope to see a DNA strands.
Thanks again for your help,
<400 power will do it... See WWM re microscopes. BobF>

Sick Betta- Tried everything with no luck.... May be BGA...   2/27/12
I am an avid reader and am so thankful to have found your site last year. I am desperate need of help. I've looked through the site and was unable to find a situation similar to mine. I have a big, beautiful red Betta. Tank specs: 5 gallons, heated between 76-78 degrees, filtered, gravel bottom, 2 live plants (both ok for Bettas) 1 synthetic plant to help keep current from filter slower. I do a 25% water change at least every two weeks, and a 50% water change once a month. I use a water conditioner and aquarium salt.
He gets a varied diet of Betta pellets and shrimp. I have studied and researched your site to try and provide him with the best care possible. Up until now he was happy, healthy and playful. In fact I was able to nurse him though a bout of Ick when I first got him with your knowledgeable help.
About a month ago I noticed dark green algae
<This might well be a Blue-green... Cyanobacteria... can be quite toxic>
 starting to grow in his tank. I tried to manage it by cleaning the spots that showed up when I'd do his water change. It got to be worse than normal so I decided to take him out and clean out the tank and gravel. I am very careful about contaminants and do my best to keep things as stable as possible in such a small system. After adding him back into the tank he was in bad shape in less than 24 hours.
<I further suspect BGA... becomes more toxic w/ attempts to remove>
At first I though it might be a stomach problem, minor swelling on his belly. I treated by adding aquarium salt to reduce the pressure and didn't feed him for several days. No change. He was and is spending considerable time on the bottom of the tank and at the top on his plants. He seems to have difficulty swimming, unable to stay at the top of the water, sinking back down.
Next I tried just maintaining his usual routine and keeping the water conditions normal as they had been, hoping he would normalize.
<This is what I would have done as well>
 He seemed to get a little better and was eating regularly again, if not as much- would float back down after two or three bites. Now he's in worse shape and the algae is back. He hasn't eaten or responded to me in the last two days now. I'm worried he's suffering and I'm at a complete loss. Please let me know if there is anything else I can do? And if not, how best to end his suffering painlessly. Thank you for your time.
<Mmm, please read here for background:
I might go the extreme route here of removing the fish... tossing the live plants... bleaching the entire system... rinsing, re-filling... and moving the fish through a few rinses (to discount the conveyance of BGA spores) to eliminate the Cyano. Bob Fenner> 
Re: Sick Betta- Tried everything with no luck....   2/28/12

Thank you so much, Bob! I went through and read the posts about the BGA- nasty stuff. I'm pretty sure now that that is exactly what it is.
<Was/is my best guess>
The tank has been getting more sunlight recently and I wondered if that was causing the algae to grow.
<Could well be>
 I know algae is common in tanks, but I wondered if this was a type that was harmful to the fish.
<There are bio-assays... I think you've been doing one>
 I'm going to remove him from the tank, bleach the system as you recommended and start fresh with the plants. I hope it's not too late and that I can get him to bounce back. I really appreciate your time to email me back. The amount of time and research that you all put into the website is phenomenal. It is so reassuring to know that there is a credible,
reliable source that I can trust.  Take care!
<And you my friend. BobF>
Re: Sick Betta- Tried everything with no luck....   Non-aq. plants     2/28/12

Hi again. I have one last follow up question. I've gone and bleached the system, replaced the gravel and added new plants (umbrella plants).
<Mmm, what is this... the scientific name? There are several popular "aquarium" plants sold that are actually not aquatic>
I picked up a new filter- Tetra whisper 10i internal power filter. It says it works with up to 10 gal tanks. It looks to be a little bigger than my previous filter, also a Tetra whisper. I'm concerned that its too strong for him, especially right now when he is not at full health.
<Likely is fine>
I've placed the plants around the filter to try and disperse the flow, I'm not sure its enough. I'm also torn because I know that the more water movement, the better to keep the BGA from growing again. Unfortunately it doesn't have a flow control. I've read through the filter posts and seen that both the gravel filters and sponge filters are recommended for Bettas.
<Or small internal or external power filters... there are even smaller units>
 I don't think I'll be able to find those in my area.
<Can be ordered via etailers like Dr.s Foster & Smith (.com)>
 I know I can order them online, however my main question is this: should I leave the filter off in the meantime?
<Yes; I would>
Second: What do you personally recommend for a filter for a 5 gal Betta tank? He's a pretty big Betta and used to be a strong swimmer...
<Mmm, you could just search w/ the string "Betta system filters"... Whisper 3i...>
Thank you again for your advice!
<Not advice; and this may seem something similar, but what I'd likely do given the stated circumstances. BobF>
Re: Sick Betta- Tried everything with no luck.... Non-aq. plants     2/28/12

In regards to the plants, they're Top Fin from PetSmart- growl - I did add some semi-aquatic Golden Ribbon plants (Dracaena variegatus?)
<This genus is terrestrial... see WWM re... the search tool>

 to float on the top which I've used before without any issues I thought, and the umbrella plants (were sold to me as aquatic, growl again. I'm not sure on the scientific name, but they do look similar the Anubias plants?).
<Also not likely truly aquatic>
 Looking on the posts regarding stocking tanks with live plants I see that PetSmart and Top Fin have used non-aquatic plants? For crying out loud, I am so disgusted with those people.
<Yes; unfortunately>
 I won't go into detail the problems I've had with them and the horrible information I've received- I've gone back after speaking with them and researched on your site to find that the information was just bad.
Unfortunately, I'm in Montana and at this point I have very little resources for my fish. Is there an online resource for good quality live plants?
<Quite a few actually. Search... read Aquariumplants (.com)>
Or is there at least one thing that PetSmart might have that would be safe for my guy?
<My fave: Ceratopteris>

 I am going to check and see if they have any of the following grasses by any chance: Anacharis/Elodea/Egeria, Myriophyllum/Parrotfeather, Ceratophyllum/Coontail. >
<These are too cold-water to be of tropical use. B>

Strange/mystery film on water surface 10/6/11
Hi crew,
Sorry I've got another one for you - hope you don't mind. Gee you lot are good.
Every morning a 55 gallon tank that I've got set up at the school I work at seems to have some sort of film on the water. Obviously I'm worried about the consequences this has for gas exchange.
I've checked with the cleaners and brokered a compromise where a bleach-based spray (pump not aerosol) they insist on using is only used on the desks. This occurred over a week ago.
Every morning I "wick" the film off (as best I can) with cloth wipes, and afterwards the surface looks like the picture attached - shot from below with killifish saying hi. As can be seen, patches of the film remain after "wicking". The film completely covers the water surface again by the following morning, if not the end of the same day. At this point, there are lots of little bubbles associated with the film.
To check if the bleach-based spray was the culprit, I set up a shallow tray filled with water next to the tank 48 hours ago (soaking a slab of granite in there too). There is no sign of the film as of this afternoon in this tray - this would indicate that the spray is not causing the film?
So I'm stumped. Presumably something in the tank is causing this? It's a new tank that's been set up a month, fish (6x dwarf neon rainbowfish, 1x Golden Wonder Killifish) in for 1.5 weeks and behaving as expected.
Moderately planted with growing Vallisneria, Indian Fern, Java Fern and Java Moss. A few granite rocks, bogwood roots, two terracotta pots and a few river stones (all rinsed/boiled/washed pre-installation as appropriate). 28 deg C, pH 7.2, Ammonia 0 ppm, Nitrite 0 ppm, Nitrate 10 ppm, GH 4 deg.
External canister filter (620 L/hr) handles the water filtering.
Thanks a lot for your help again crew - champions.
<Hello Duncan. If this is what I think it is, it is not uncommon. It's similar to the "protein" that accumulates in protein skimmers in marine aquaria. I think it's a byproduct of biological processes in the tank, and in itself doesn't do any harm. Try increasing agitation of the water at the surface, e.g., with an airstone or a spray bar. If my hunch is correct, you'll see the stuff go away by itself. Cheers, Neale.>

Re: Strange/mystery film on water surface, now BGA 10/6.5/11
Great stuff Neale,
I lifted the spray bar up from about an inch below the water line to level with the water line this morning, much bubbling ensued and the "protein" scum appeared to have cleared by the end of the day. Yay! Bit worried about CO2 drive-off and subsequent plant-growth issues (the floating Indian fern seems to be being beaten around a bit too), but I'm sure it'll be fine.
<Glad this worked. Yes, extra turbulence drives off CO2. But the flip side is that no turbulence encourages precisely the sort of slimy, stinky water you see in ponds. Getting the balance right is the tricky bit!>
I've got another one for you, sorry. I've observed 7 or 8 patches like the picture attached on the gravel substrate of my month-old aquarium. I believe this is blue-green cyanobacteria. Having read Bob's WWM article on the subject, will the extra aeration provided help deal with this? Given the rest of my tank parameters (outlined in previous email) plus my small portions of mini-pellets, wet-frozen blood worms and shelled, squished peas that the fish get fed (all eaten within 1-2 mins), I'm not sure what else to do? This began as a single colony on a Java moss frond 5 days ago, but seems to have spread since then.
Thanks so much team,
<The clue here is where the BGA started -- on the moss. Why? Because moss traps water and reduces current. BGA just LOVES still water conditions.
Almost always, you see it around moss clumps, on the leaves of Vallisneria at the top of the tank, on gravel against the glass, on the feathery roots of floating plants -- all places with low or no water flow. While I know many argue nitrate and phosphate are the major issues, I've got heavily stocked tanks with high nitrate levels and yet no BGA at all. But I also run those tanks at high water turnover rates, 6-10 times the volume of the tank in turnover per hour. My experience is that the more current, the less BGA; whether it physically can't get established or the higher oxygen levels are critical I cannot say. But there it is. Physically remove what's there now, rejig water circulation around the bottom of the tank, and then hope for the best. Cheers, Neale.>
Re: Strange/mystery film on water surface 10/6.5/11

P.S. Sorry, forgot to mention I'll be doing a 20% water change and gravel vacuum tomorrow, my first for this 1 month-old tank. It'll 20% weekly after that.
P.P.S. Going back to an older issue: water pH 7.2-7.4, GH 4. Neale speculated that higher KH may account for the slightly basic pH, in spite of the soft GH. I Measured KH today with a new API liquid kit - KH is 3. So my water is officially soft. So what gives with the pH? Is this a bit weird (Ammonia 0 ppm, Nitrite 0 ppm, Nitrate 10 ppm)? I'm not worried, just interested.
Right, I'm gone now,
<Well, one problem with pH is that it isn't only affected by carbonate hardness, though even a carbonate hardness of 3 degrees KH could result in a slightly alkaline pH like the one you see here, particularly if there's little pushing the pH downwards into the acidic range. So I wouldn't worry too much. Provided it's stable, pH 7.2-7.4 is a great range for a wide variety of fish, including soft water species, which are less bothered by pH than total (general + carbonate) hardness. Cheers, Neale.

Fish itching... not Ich or velvet -- 06/25/11
Dear crew,
Some of the fish in my planted low-light 30g aquarium are itching'¦ it started off with one of four of my Corydoras habrosus a week ago... I just thought maybe this was normal, as I had acquired them about 2-3 weeks prior. However, the other three since became "lazy" and just keep to themselves in a corner, but do go up for a breath. I also thought this was normal, with them being nocturnal.
<Four is rather too few for this dwarf species; even for large Corydoras species a group of four would be shy and hide away during the day. Keep C. habrosus and other dwarf Corys in groups of at least six, and realistically a dozen or more. They're cheap to buy and don't place much demand on the filtration system, so there's not really any excuse.>
Additionally, in my current war against blue-green algae, I added 4 zebra Nerites during a blackout 2 weeks ago as I heard they eat some BGA.
<Hmm'¦ no, not really much good against cyanobacteria. There is a brackish to marine species, Puperita pupa, that may eat cyanobacteria, and because it's called the "Zebra Nerite" by some, it can be confused with the freshwater species commonly traded, such as Neritina coromandeliana. That species only eats green algae and diatoms.>
Today I saw one of my Neon tetras flash himself against a plant. At this point, I am sure it must be a disease.
<Well, Neon Tetras suffer from several diseases and have a poor survival record in hard water, so above all else, be aware that you won't have much success with Neons unless you buy good-quality stock and keep them in coolish (22-24 C) water that is soft (1-10 degrees dH) and slightly acidic (pH 6-7).>
It is not Ich or velvet, I think. On my fattest neon, it seems there are punctures in the skin (I can't really tell). Other than that and the flashing, it does not seem there are any other symptoms.
Water parameters are all at correct levels, so I'm not concerned about that.
<You may not be, but I am! Without some declaration of the water chemistry and water quality in actual numbers, I can't help much.>
Water changes are 25% every Saturday.
Looking forward to your response'¦
<Likely a variety of environmental issues at play here, as well as stocking choices that may need to be revised. Do understand that cyanobacteria indicate fundamental problems with an aquarium including high nitrate and phosphate levels; poor water circulation at the bottom of the tank and/or around plants; and insufficient lighting. Review, and act accordingly. Cheers, Neale.>
Re: Fish itching... not Ich or velvet -- 06/25/11
Hello Neale,
Thank you for the information about the Nerites.
<You're welcome.>
I suppose I'll keep them anyway, their shells are quite pretty and I'm sure there's enough diatoms and green algae at the back and right panel of the tank... I never clean those unless Cyano is growing immensely on them. Less than two months ago, my tank was covered in the stuff, for the past 3 weeks I have gained the upper-hand on the stuff and now it is really reduced to just small patches. I think you'd be impressed! I improved the tank dramatically'¦ extra circulation, improved maintenance, more suitable plants (this is a low-light tank)'¦
<Ah, yes, sounds good. Agreed, Cyanobacteria are easiest to "fix" by improving things and letting other plants, algae regain control.>
Anyway, the tank is stocked as follows...
1 Rummy Nose
2 Harlequin Rasboras
5 Neon Tetras
8 Glowlight Tetras
1 Clown Pleco
1 Dwarf Gourami (surprisingly healthy...)
4 Salt & Pepper Corydoras
4 Zebra Nerites
4 Amano Shrimp
<Hmm'¦ not completely surprised the Corydoras habrosus are hiding, given their small size compared to some of these tankmates.>
I know the tank is probably overstocked, but I'm going to be moving the rummy nose and harlequins to another tank soon. I don't know if I can add anymore C. habrosus?
Water parameters:
Ammonia: 0ppm
Nitrite: 0ppm
Nitrate: 20ppm
PH: 6.7
GH: 10dH
Temp: Maintained at 75F, but these warm Summer temperatures are bumping this up to 78-84.
Tank is injected with DIY co2.
<May be redundant in a low-light system, and in fact may even cause problems. Remember, CO2 isn't the limiting factor in a low-light system, and the slow-growing plants wouldn't care anyway. So you have this extra variable that could be displacing oxygen and lowering pH. Review, and act accordingly.>
Thanks again.
<Cheers, Neale.>
Re: Fish itching... not Ich or velvet -- 06/25/11
The inhabitants appeared more happier once the water was made more acidic and soft.
<Fair enough.>
I also think it affected the Cyano, presumably because bacteria has trouble in acidic environments'¦
<Don't think this is likely'¦>
The plants also seemed to do better.
Does this have anything to do with my original problem?
<Hard to say. Do review the various things mentioned in previous messages. Cheers, Neale.>
Re: Fish itching... not Ich or velvet -- 06/26/11
Good morning my friend,
It does appear the fish have definite symptoms of a disease. Last night, before lights out, one of the Neon's red line had lost a lot of it's intensity.
<Neons do lose their colours at night, as you probably have noticed already. But if their colours go during the day, that's a sign of stress and/or disease. It isn't one particular thing, though Neon Tetra Disease is the most common species-specific problem Neons die from (of course more Neons are probably killed by poor water quality, predation by Angelfish, being kept too warm, being kept in hard water, and so on).>
At the time I also noticed my Espei have an incomplete orange colouration (i.e., they're missing a patch of orange). I was concerned it may be the dreaded Neon Tetra Disease.
<Quite. NTD is essentially untreatable, and infected fish should be euthanised (see WWM re:, but 30 drops of Clove Oil in a litre of aquarium water does the trick nicely).>
This morning, it appears there is a cloudy coloured patch on one of the neon, but the neon has regained the intense red it had. The growth does not look cottony.
<May be either Finrot, Fungus or something called Mouth Fungus, actually a bacterial infection, Columnaris; do see WWM re: distinguishing them and treatment.
Some useful medications, e.g., eSHa 2000 in the UK and Seachem Paraguard in the US treat all three.>
The Gourami is being his usual arrogant self and doesn't seem affected by anything. The Rummy nose has a real intense red nose... The glowlights are well too.
Please help'¦
<Have tried. Cheers, Neale.>

Red algae, FW, guppy hlth., using WWM 3/29/11
I set up a 10 gallon (heated, aerated, and filtered) fish tank recently, it has 2 guppies and a few ghost shrimp. It was all going smoothly until I added the shrimp, suddenly red algae exploded in the aquarium.
<Mmm, the color itself can be misleading... does this material feel very slimy? It's likely Cyanobacteria/BGA>
I clean it and it covers the aquarium again in around 2 weeks. Nothing online has been very helpful.
The crew has been of great help in the past, so it`d be great if you could help me out again.
<Read here: http://wetwebmedia.com/FWSubWebIndex/fwbgafaqs.htm>
Also, I had a guppy that would swim mid-tank with its mouth pointing toward the surface, though it was capable of swimming normally and also had a bent spine. I was told it was because of previous conditions in which I regrettably and ignorantly kept it (in a small, one gallon with another guppy, ouch). It seemed to be reasonable fact until recently the guppy died and another one seems to be taking up the habit of the deceased. The body of the deceased seemed untouched when I pulled it out. Any suggestions on what the problem may be?
<Please learn to/use the search tool on WWM; it's linked (on the left shared border/.dwt)... to here: http://wetwebmedia.com/Googlesearch.htm
and put in the string: "guppy bent spine", read the cached views. Bob Fenner>

Algae or Moss? 10/4/10
Hello All,
After conquering diatoms, BBA, Hair algae and green spot algae, I am now battling a new type that I cannot find online. It looks brown with some green in my pictures but as I see it in my tank, it is all green. There are parts of it in the pic that show green and that is what color the entire patches are (I don't know why my camera showed brown, even with the flash) but please see the green in the last pic and that is what it all looks like. It's a really pretty, deep green too. It is located only in the front of my tank. Patches of it in the front section and actually along the whole front edge and even creeping down the front of the plexi where the substrate layers are seen (see second pic). It isn't hurting anything but I just don't know what it is. I have noticed it is beginning to climb on a white ceramic decoration so it's not limited to the substrate only (see third pic). Have you seen this before and know what it is? When I syphon, it will come up as a big piece, like carpet. It does seem to resemble some type of a moss or fungi, like what is found on old vegetables in the fridge. So far, I haven't found anything online and want to be prepared to remedy this in the future if needed, since I have had my hands full dealing with every type of algae there is (and I do have thread algae but it's not a big problem)....ugh. Any help will do.
Thanks you all!
<Hello Lisa. This is Blue-Green Algae, also called Cyanobacteria. Despite the name, it comes in a wide variety of colours including black, red, and green-blue. Blue-Green Algae occurs most often within a particular set of conditions. These are as follows: [1] slow water movement; [2] high nitrate and phosphate levels; and [3] excessive light, particularly sunlight. It often starts on the bottom of the tank because that's where water flow is often weakest, and you usually find the BGA growing around plant stems precisely because these slow down water flow even more. The cure for BGA involves maximising water flow at the bottom of the tank -- if you have BGA in your tank, it's VERY likely you don't have enough filtration or water turnover. You also need to do more water changes to keep nitrates and phosphates down, or conversely, reduce stocking and/or feeding. Finally, you need to review lighting. Good strong light is essential for plant growth, but if you don't have plants that are growing quickly, BGA will take advantage of the excess light and nutrients. From the photos you have, it looks like you have a very plant-unfriendly substrate, and the plants you have, which look like Dwarf Amazon Swords, require a good substrate and
strong lighting, and your specimens appear very unhappy. You also seem to have Java Ferns stuck in the substrate, which they hate. They're epiphytes!
Trust me when I say that if you have happy, fast-growing plants in a tank with a strong water current and low nitrate levels, BGA doesn't grow.
Siphon out that which is visible now, fix environmental conditions, and the problem should go away. Cheers, Neale.>

Blue-green algae and fin rot - what to do next? 5/15/10
Hello and thank you so much for this wonderful Web site.
I have been very grateful for your help in the past so am reaching out once again for advice. My 25 gallon tank has been plagued with blue-green algae for about 3 months -- ever since I adopted out the Plecostomus that kept it clean but had grown to large for the space.
<Whatever else is going on, the blue-green algae has NOTHING to do with the Plec. These catfish DO NOT eat blue-green algae, so there usefulness in this regard is nil. Indeed, because they can create nitrate- and phosphate-rich conditions in small aquaria, they are much more likely to CAUSE algae problems of this type.>
Not wanting to use an algaecide or antibiotic, I have just been manually cleaning off the algae when I do water changes (about 10 gallons every 2-3 weeks). I also completely blocked the tank from any sunlight. Still, it seems to take only about a week for the slimy green stuff to reappear and the water to take on a strong algae smell.
<Correct. Blue-green algae will come back if conditions suit it, no matter what you do. The solution is to create conditions blue-green algae doesn't like! Simple, really.>
I have a hood light that runs about 11 hours a day and have wondered if I should just turn it off for a while, but worry that the plants will die. My next move was to try adding plants.
<Does depend on the plants. Blue-green algae are best controlled by ensuring four things. Firstly, the tank doesn't get direct sunlight. Secondly, there is a strong water current throughout the tank, and especially wherever it is the blue-green algae is most prevalent. Thirdly, nitrate and phosphate levels are kept as low as is practical. Fourthly, if you can, the addition of fast-growing plants, ideally floating plants, can make a huge difference. Very few fish or snails eat blue green-algae, so control of blue-green is all about prevention rather than cure.>
To complicate matters, more than half of my fish are having problems with their fins ... some are split, others are ragged around the edges, and in one case a good chunk of the tail has just gone missing. Could the algae have anything to do with this?
<No. But conditions that favour blue-green algae, i.e., poor water quality and inadequate water circulation, are precisely those that favour Finrot.>
I don't think it is from nipping and the water tests fine--pH 7.4, ammonia 0, nitrite 0, nitrate 5, phosphate .25, KH 2, GH 3.
<These are both very low. What kinds of fish are you keeping? Many fish and most plants will not be happy in water this soft.>
There are only 12 small fish in the tank--10 tetras, a Cory cat and a juvenile Bristlenose so it doesn't seem like overcrowding is the problem. Would you recommend medicating the tank at this point, and if so what would be your drug of choice?
<Medicating against Finrot is really only part of the solution. You need to establish why this tank is so unhealthy. Fix that, and the Finrot problem should be easy to fix with a standard medication and a bit of time.>
Finally, do you think the undergravel filter could be contributing to these problems?
<Undergravel filters will certainly inhibit the growth of plants that have roots, and dying plants won't help things at all. Undergravel filters need to be set up right to work properly. Check you have adequate water flow, enough uplifts or powerheads, a deep enough gravel bed, and the right grain of gravel.>
The tank has been set up for about 9 months and although I regularly vacuum the gravel I've never cleaned underneath the plate.
<Shouldn't need to more than once every year or two.>
I can see below and it does look pretty green. I have considered disconnecting the undergravel as there is also a H.O.T. magnum canister and a Biowheel filter running. Just not sure what is the smartest thing to do next and appreciate any advice you can offer.
Thanks so much,
<Cheers, Neale.>

Freshwater fungus...? 2/25/10
I'm wondering what this white "fungus" growing on my gravel and driftwood is. It's almost like a film.
<Most probably some type of bacteria, perhaps a Cyanobacteria. Fungus certainly does grow in freshwater aquaria, but usually on organic-rich substrates, like freshly cut wood. Bacterial films tend to develop where
the substrate is dirty (i.e., rich in organic matter) and when water current is weak. Cyanobacteria likewise, but with the additional issue of direct sunlight often being the trigger. Cheers, Neale.>

Bright Orange Algae, FW 10/27/09
I have a freshwater tank. I recently switched from a 100 gallon tank to a three hundred gallon tank and suddenly noticed bright orange algae growing on my fake plant and the top of a shell in my freshwater. What is this stuff I have never seen it before??
<Probably just algae, and if its orange, then the chances are it's blue-green algae (Cyanobacteria) which, despite the name, needn't be blue-green in colour. Blue-green algae has a distinctive musty smell, and
when you look at it, it's slimy and made up of tiny threads all matted together.>
I looked on your site and really only found stuff for saltwater.
<Do see here:
Thanks do much
<Cheers, Neale.>

Re: Bright Orange Algae 10/29/09
Thanks so much the info is greatly appreciated. Is this blue-green algae bad?? or poison, because I kinda like the look of it as long as it does not spread to everything?
<Blue-green algae is not in itself usually poisonous
<<RMF disagrees with this statement. Some BGA is VERY toxic indeed>>
(though in large amounts, it can consume oxygen from the water, harming the animals in the tank). However, blue-green algae usually only develops in tanks that have
underlying problems. So they're an early warning that something isn't right. Typically, blue-green algae grown in tanks that [a] have poor water circulation; [b] have high levels of nitrate and phosphate in the water; and [c] are receiving strong direct sunlight. Without fixing these problems, it grows very rapidly, and long term, can cause problems in itself. Cheers, Neale.>

Question about algae (Cyanobacteria) 3/20/09
I have got this wicked algae growing on saltwater shells in a 55 gallon freshwater tank. As well as a couple of other tanks. Primarily my African cichlid tanks. I am attaching a photo graph of some of the shells. Could
you tell me what it could be? Thanks. James Kittrell
<Looks to be generic blue-green algae. Your Mbuna won't eat the stuff, so in terms of control, you need to manually remove it. But more generally, blue-green algae thrives under a trio of conditions: poor water movement, high levels of nutrients in the water, and the presence of direct sunlight.
Because cichlid tanks are often overstocked but under-filtered, blue-green algae can be a common problem. In itself blue-green algae isn't a bad thing, but it does indicate relatively poor conditions. Doing more water changes and ensuring adequate circulation of water are helpful. Blue-green algae often grows on the sediment or around plastic plants before anything else because it really likes pockets of still water. In Mbuna tanks you need 8-10 times the volume of the tank in turnover per hour; i.e., a 55 gallon tank needs a filter rated at around 550 gallons per hour.
Hang-on-the-back filters and internal canister filters cause specific problems because the inlet and outlet openings are close together, so even if you have lots of turnover, the end of the tank far from the filter can
become relatively stagnant. So if you use hang-on-the-back filters or internal canisters, put one at each end so that all the water moves about.
If you have an external canister, then putting the inlet pipe and outlet spray bar at different ends of the tank will do the same thing. Cheers, Neale.>

Re: Question about algae (Cyanobacteria) 3/20/09
Hello. I was at my friend James' house last night and he showed me the algae on several shells in 3 separate aquariums... it is not any kind of Cyanobacteria that I have ever seen... It is not slimy, doesn't break apart,
and is extremely difficult to remove ( kind of reminds me of "green coralline" algae ...)
<More than one type of Cyanobacteria. While many are slimy or furry, others are more like what you describe. It's the colour and the way the "algae" covers the shell that makes me think it's Cyanobacteria, though the photo was too blurry to be sure.>
It is more of an encrusting type of algae and has a rough texture in and out of water... What reminds me of coralline however is the way in which most of it grows... in circular shapes that eventually form a film
appearance (like the photo he sent you)
I will tell him to e-mail you a couple of the shells that have less growth so you can see what i mean... Another interesting fact is he first discovered them in his Frontosa broodstock aquarium... the algae first grew completely buried under the gravel... fungi?
<No. Sounds a lot like Cyanobacteria. The thing about Cyanobacteria is that some are obligate anaerobes, that is, they cannot grow where there is a lot of oxygen. (In evolutionary terms, photosynthesis evolved first, and only once there was lots of oxygen in the atmosphere did the bacteria then have to evolve a way to deal with all this nasty, dangerous oxygen. Some bacteria never "learned" how to do this, and remain in anaerobic mud, just below the surface, where they can get some light but are removed from the oxygen.)>
Just shooting into the car far out past left field...
<It could be something else, but for now, I'd put my money on Cyanobacteria.>
Thanks always
<Always a pleasure. Cheers, Neale.>

Red Slime Algae 12/7/08 Hi, I have a question about red slime algae and a possible way to get rid of it. I ask my local fish guy what is a best way to get rid of it. He says that he has some pupfish that love red algae. But on your site you stated that there aren't any clean up crews. So will they help at all? But am going to take the red algae out by hand and hopefully get a siphon. But will a pupfish help keep it down in the future? thank you very much, Amber F. <Pupfish (non-annual Cyprinodon-type killifish) can and will eat many types of algae including blue-green algae (or Cyanobacteria, of which red slime algae are a type, despite the name). However, the problem is that blue-green algae grow very rapidly, and they're also specific to tanks with certain types of problem. In particular, tanks with poor water circulation and/or high levels of nitrate and phosphate. Unless you fix those problems, adding new fish, even those that eat algae, will simply make a bad situation worse. By far the best "fix" is to give the tank a thorough clean, siphoning out any and all blue-green algae. Then review conditions: upgrade filtration and reduce stocking as required. Ensure water circulates throughout the tank, and ensure you're keeping up to date on water changes (25% per week is the minimum for busy freshwater community tanks). Lots of folks make the mistake of seeing algae as something that needs fixing by adding livestock; in fact algae is very specifically a sign that a tank isn't balanced, and is a warning sign of other, less obvious problems brewing in the background. If you add livestock to an already unbalanced (overstocked) tank, all you do is add more nitrate and phosphate to the system, tipping the odds in the FAVOUR of the algae, making things worse. A balanced tank with the right numbers of fish, plants, invertebrates and water volume will normally have little algae generally, and usually no blue-green algae at all. Cheers, Neale.>

Interesting fact/fiction about Cyanobacteria 9/13/08 Dear Crew, <Andy> I was perusing Reef Central and came across a thread on the use of red slime remover to eliminate Cyanobacteria. Whenever I see someone advocating for its use, I try to jump in and advocate AGAINST its use, explaining all the reasons for my opinion, directing them to WWM, etc. In any event, one response to this thread stated that when Cyanobacteria dies, it releases cyanide. <?> At first, I started laughing and thought "this is a ridiculous statement"--the guy is clearly confusing "Cyano" and cyanide. But, I did some research on the internet and found some sites that state studies have shown that all forms of Cyanobacteria release cyanotoxins and cyanide when they die rapidly, such as would happen when erythromycin is used. See here for example: http://www.alken-murray.com/Cyanobacteria.htm. <Mmmm> Before I searched the internet, I searched WWM for information. I found very little to confirm or debunk this statement. I did find one post by Bob addressing a poster's question about why his/her sea horses might appear to go limp after hanging onto and breaking up BGA in which Bob implied/stated that the sea horse is getting a dose of cyanide from the BGA. <Mmm, I hope not... Cyanobacteria are known to degrade cyanide/s...> However, I also found the following posted by Neale in the FW section: "BGA doesn't kill fish. The idea that it is poisonous comes from non-biologists confusing the name of the group of bacteria (Cyanobacteria) with the word "cyanide". In fact the "cyan-" part of the name refers merely to the colour. There are in fact some fish that eat the stuff, as well as snails and other invertebrates. Anyway, it is best dealt with by balancing the tank[.]" <Mmm, and I do disagree with this statement. A cursory look even on the Net will show that BGA decomposition does release deadly materials> If Cyano does in fact release cyanide into a system when it dies rapidly, this is just one more reason to never use this product. Can anyone at WWM confirm this or offer any further insight into this? <Mmm, cyanides are any triply bonded carbon/nitrogen... attached to other matter... There may be "some" cyanide in Cyanobacteria, but I warrant very little... the commonality with the names "Cyan", meaning blue is a bit confusing perhaps... but these bacteria (and indeed ourselves) have biochemical mechanisms for degrading cyanides within our tissues, not producing, or releasing such> If this is true, you might want to edit the article on BGA to make this clear to all potential users of red slime remover to drive home the point that this product is dangerous. <These products, use is indeed dangerous... for the general reasons stated... the release of toxic factors, and possible rapid reduction of dissolved oxygen. What's more, their use will not eliminate the root cause/s of BGA proliferation: http://www.google.com/search?hl=en&rls=com.microsoft%3Aen-us%3AIE-Address&rlz=1I7PCTA&q=cyanobacteria+control+toxicity> Take care! Andy <Bob Fenner>

Re: Toxicity of Cyanobacteria 9/13/08
Hi Bob,
<Msieu Neale>
Read your FAQ answer on Cyanobacteria. I have to confess to talking from the freshwater perspective, and so far as I know there aren't any directly toxic forms that occur in aquaria. Multiple species of fish consume the stuff in the wild, e.g., Cyprinodon spp. killifish and Ameca splendens. I would certainly agree that a mass die-off of these algae -- or indeed any algae -- isn't a good thing, and quite likely oxygen consumption through mass decay is as much a threat to livestock as anything else. As for marine Cyanobacteria, quite a few are known to be very toxic indeed, apparently "hundreds of times" more toxic than potassium cyanide. http://www.interciencia.org/v21_06/art01/summary.html But I still haven't read anything that states Cyanobacteria actually contain/produce cyanide at or above the levels present in other photosynthetic organisms.
<Mmm, yes... some are known to contain... "some". A bunch could be discussed re aminonitriles...>
As you doubtless know, cyanide compounds are all around in the natural world, particularly plants, most famously being quite concentrated in peach stones and almonds. Cheers, Neale
<And you, BobF>

Cyanobacteria. Non use 8/6/08 Hi Bob, I live in Portugal on the lee shores of a large man made dam used for irrigation purposes. <I see> Have just seen a notice in the council offices that there is a concentration of Cyano bacteria, which I presume is Cyanobacteria in our area. Now I intend to cut the grass that has been growing under the water now that the level is receding, and making it into hay . <Mmm> Can the hay made, after being exposed to temps of 30C+for a few days , contain any bacteria that could be harmful to the livestock that consumed it.? <Unfortunately yes. I would bury this material.> I look forward to your reply. Regards. Bill Halstead. <Ahh, a famous name. Bob Fenner>

Blue Algae (Cyanobacteria) problem. 4/1/08 Hello, I noticed several small patches of blue algae in my new 46-gal tank. My mistake was to move some plants from the 10-gal to the 46-gal thinking that what was in the 10-gal was simply algae. After some research I understood that what I thought was algae is instead Cyanobacteria. I also read that this pest is extremely difficult to defeat and I'm starting to get a bit nervous. <Don't get paranoid. It doesn't do any harm. Unsightly, yes. But it doesn't harm the fish or plants. Remove manually, and then minimise re-growth.> I see there are antibacterial remedies on the market, but I'm afraid to kill the good bacteria as well. <It doesn't. It's merely Erythromycin. While it certainly kills the blue-green algae (BGA), you have to remember having a lot of decaying stuff in your aquarium isn't a good idea for obvious reasons. Much better to manually remove. In any case, however you kill/remove the BGA, if conditions suit, it'll be back within weeks.> Some people suggest a 3-day blackout. However I also read that the bacteria goes dormant during the blackout and comes back when the lights are back on. This last approach could also damage the plants that I have in the tank for lack of light. Do you have any suggestion? Thank you, Giuseppe <Eutrophic conditions and pockets of still water, coupled with poor plant growth, tend to be the factors that allow BGA to develop. Direct sunlight is one triggering factor. So, increasing water circulation and increasing the amount of plant growth (which may mean more artificial light) will help. There's no sure-fire cure for BGA, but slow-moving, nutrient-rich water is what it likes best. Cheers, Neale.>

Re: Blue Algae (Cyanobacteria) problem. 4/4/08 Neale, thanks for your always prompt reply. The affected tank has a bit more than 3 Watt/gallon of light, a DIY CO2 system and laterite mixed in the substrate. The filter is also pretty powerful and creates enough circulation to move some leaves slightly. Do you suggest to add a water pump to increase circulation? <All sounds pretty good. I'm surprise you're getting BGA at all. It is possibly a transient problem, and if you siphon out any patches of infected sediment, and crop and covered plants, you might find thing improve once the new plants start growing. Adding additional water current, or at least redirecting the current you have, could help. Adding too much bubbling is a bad idea if that drives off CO2, so powerheads are better than airstones. BGA simply seems to do best where the water flow is slowest though.> As for slow plants growth, do you think I should add any kind of fertilizer? I'm a bit concerned that adding fertilizer would harm the fish, but I've heard that people add fertilizers. <Yes, fertilisation is important. No substrate will feed the plants indefinitely. Eventually at least one element will be used up, and that'll be the thing that slows down plant growth. Aquarium fertilisers shouldn't harm fish if used properly.> Thank you, Giuseppe <Cheers, Neale.>

Bluegreen algae, Nitrate/phosphate/ light relationship? 3/30/08 Greetings all! Some back ground on the issue, hope it is not too much for the basic questions I have: I service a 90g cichlid aquarium, currently has 6 med size fish, 2 pc driftwood-I read this may be an issue but was not in the beginning. pH runs 7.2-have been bumping it up-was originally set up with regular aquarium gravel, NO3 is 0-5 , 3 dKH- may rise soon as have been adding cichlid substrate temp 78. No ammonia nor nitrites.. I average 30-45% water changes.. has an Emperor 400 type filter.. I recently added a Magnum HOT filter and have been using HBH phosphate pads since mid Feb.. An automatic feeder was put into service also in mid Feb, prior the tank was hand fed.. quite possibly over but it never showed up in the NO3 tests..... I have been servicing this aquarium bi-monthly for the past several yrs with basically no problems. When I first started it had a UV sterilizer that was not utilized and the tank two ends were covered to prevent light getting into the aquarium. It appears as though there is a light on 24/ in the same room as it is in a nursing home. It did have a removable front cover to give the aquarium darkness, but somehow the cover walked off long ago... Last May I removed the end covers as it make the tank too dark IMO and the residents could view the fish from the ends as well.... Last Oct the tank started getting blue green algae- Cyano rather badly and quite suddenly.. I was rather slow to react.. I only did large water changes for the first few months, to no avail. I finally understood this was basically like the Cyano in SW aquarium so I started using Phosphate pads, increased flow by adding a powerhead- and started adding the cichlid based substrate. In mid Feb the feeder was installed as I believe that more that one person was feeding the aquarium..... Since I started this regime, the tank has and is improving significantly..... however the client and I have somewhat butted heads over the cause and how I should have addressed it... I should also point out I service 2 other aquariums-ones that I set up about 2 yrs ago with aragonite sand or cichlid mix , using the same water source and have had no problems. <Blue-green Algae is almost always related to eutrophic conditions and insufficient water movement. Bright light, particularly sunlight, can be a triggering factor but does not in itself seem to be the cause. BGA often develops where water movement is lacking, e.g., around floating plants or on the substrate. So the first thing to do when BGA becomes a problem is to check the water circulation. Adding powerheads and/or airstones is certainly an option in a cichlid tank given that cichlids tend to enjoy a strong water flow. But you should also check your filters provide not less than 6 times the volume of the tank in turnover per hour.> The client insisted that we needed a Pleco, there was too much light, from me taking the end covers off and the UV filter should be in service. <Plecs don't eat BGA so neither here nor there. In fact, adding a Plec will increase eutrophication of the water, making BGA more of a problem rather than less. Paradoxically perhaps, adding light can help if you also add fast-growing plants. This is because the plants have an allelopathy effect that suppresses algae and BGA growth. UV filtration can help with BGA or algae problems to a degree, but it isn't a cure and it does depend on the UV filter being maintained properly (cleaned, tube replaced). But really BGA is very difficult to fix unless you deal with the underlying causative problem. As you'd imagine, the bacteria involved are tenacious and present in all aquaria, so even if you "fix" the problem with antibiotics (one common approach) the BGA can grow back again in weeks.> I tried as I could to inform them this is not an algae and was not caused form the light.. and also I did not believe the UV system would impact it much as it had not been in service since I started cleaning the aquarium. I am told that this happened once before, and the other service person installed a UV and covered the tank to keep out the light. I am not sure what kind of algae they had and am not sure they really know either... but I do not think it is important for now.... <Agreed.> What do you suppose caused the outbreak? <As above.> Wouldn't a high PO4 level go along with a high NO3? <Depends, but regardless in a cichlid aquarium there will always be enough to potentially drive algae/BGA growth. Remember, both these classes of organism naturally inhabit waters with minimal amounts of nitrate and phosphate. So even a "clean" aquarium is as eutrophic as a swamp in comparison.> Is there a reliable test kit for PO4? <Yes, used by marine aquarists.> Why did large water changes basically have no effect on the Cyano..? <Don't know, but I agree it doesn't.> In your opinion, would a UV sterilizer make any difference? <By itself, no.> Would the ambient light really be an issue? <A triggering factor in my experience. At certain times of the year when sunlight strikes a fish tank for a certain period, I've noticed BGA patches just at the sunniest spot. But regular aquarium lights don't seem to be a major issue. I've seen BGA in dimly lit tanks, and brightly lit tanks with no BGA at all. Next to me here is a community tank with rocks and regular algae but no BGA at all; when it had half the light it has now and lots of plants making the water more still, BGA could be a real problem.> Sorry for what may appear to be rambling but I would like to know what may have caused this to occur..... <Check for sunlight, increase water movement, maintain good water quality.> Thanks for your time and attention! Regards Denise <Cheers, Neale.>

Red-orange residue in freshwater Cichlid tank... Likely BGA... 2/18/08 Hi!! <Hello Christina> I have a 75 gallon tank that has been set up since Xmas of 2007. It cycled very well and houses African Cichlids of various types. Everyone is happy and doing very well...I have two female holding eggs and possibly one more, not sure yet. About two weeks after setting the tank up I notice a red-orange slime that started to cover everything in the tank. <Yuck!> It is very obviously coming from the surface as it does not cover surfaces under plants or other decorations. I have had no Cichlids die though I have twice put in an algae eater (Plecostomus) and they both died within two days. <Yikes> Recently I clean all decorations, did a 50% water change and within one week the slime was back. <Good name for it... is likely to some large extent a Blue-Green Algae... aka Cyanobacteria... many can be quite toxic to ingest> The city says it's the water system we have that removes all chlorine, <Mmm, the system you have at home? As in some gear to treat the potable source> but the water system people tells us that it's the city water and is a result of oxidized iron settling in the tank. <Mmm, doubtful... not this amount... not to where you can actually see it accumulate> I am at a loss and very disappointed because the tank looks so bad. At least my little guys are okay right now. Any insight would be wonderful. Thank you so much for you time, Christine <Mmm, there are a few approaches to limiting, controlling BGA... More circulation, chemical filtration, sequestering microbiologically, competition with other photosynthetic life, nutrient export... Please read here: http://wetwebmedia.com/FWSubWebIndex/fwbgafaqs.htm and the linked files above. Bob Fenner>

Re: Orange slime, FW algae ID, contr. f's 2/19/08 Thanks so much Bob...I will read up on that link right now. I forgot to mention that we also have the red color in our showers and toilets. This is why I think it's the water and not something in the tank. <Mmm, maybe, but just a small possibility these are the same... the shower is likely a ferrous stain, but the pix you sent show an algal sort of growth...> Our water system guy did say that coquino has a lot of iron in it, but I didn't think it would be so high as to leach in and settle so quickly. <Mmm, no... if this "high", the life would be gone entirely here. The iron however is likely aiding the BGA... > Our system is a softener with a carbon filter. I attached a couple pictures and now that I'm looking at in in the pictures it seems more orange-brown. In the first picture you can see how it settles as there is a distinct line where there is no slime. Can algae grow so quickly? <Oh yes... some forms/types can double their biomass every few hours...> Two weeks ago tomorrow this tank was very clean of this slime. Thanks again for all you help Christine PS...That is my female Yellow Lab that has been holding eggs since last Tuesday...any idea when they might hatch??? <Should be within four days or so at temp.s of the higher 70's, low 80's F.> Thanks again!!! <Do read re means of limiting this algal growth... Bob Fenner>

BGA/silicate connection 11/9/07 Hi guys, Scott here. For the second time in about a year, I am battling BGA in my 20-gal freshwater tank. The tank is heavily planted, with a 65-watt Corallife compact fluorescent fixture. The bulb is about a year old. Java fern, Java moss, Wisteria, A. nana, corkscrew vals, and something I think is a variety of crypto are all producing new growth without CO, and little supplementation. Rotala indica not so well, but still has new growth. <Sounds like insufficient light. Rotala is a plant that is a weed under bright light, but does nothing at all under inadequate light. For example, I've stuck this species in a garden pond and it has survived and grown even under ice! But inside moderately illuminated aquaria, it just slowly dies. If light isn't the issue, check the substrate and CO2 concentration: both of these are key factors for Rotala.> For some reason, the rhizomes of my banana plants rotted away, but they continue to produce new growth. <Hardly the most reliable plant in the hobby. They need very specific water conditions depending on the species in question. Seemingly little adaptability.> The main problem has been BGA that grows over the lower leaves and chokes them off. <Common problem. Water quality (nitrate and phosphate especially), overheating, and direct sunlight are all critical triggers for Blue-green Algae. Often, treating with antibiotics is the only quick way to completely eliminate BGA, but if you get good plant growth and stabilise water quality, eventually it fades away.> I am using straight well water, which I have tested for silicates at around 10mg/l. <Silicate isn't really an issue with Blue-green Algae. Diatoms perhaps, but even in freshwater aquaria Diatoms aren't normally a problem except in immature tanks or tanks with poor lighting.> Sometime in the last few months, the pH of my well seems to have increased from 7 to around 7.4. The tank tests between 7.4-7.8. Phosphates are under .25. One of my local LFS insists that the silicate is what is feeding the BGA. <No, it's really not. Silicate is hardly used by most organisms. Diatoms almost uniquely use silicon to produce their external "shell".> I am considering an R/O unit, because I also have some funky-looking stuff growing in my saltwater tank. I guess the main questions I have are: Is the silicate likely the BGA culprit, and if so, will an R/O unit make that much difference? <Reducing the phosphate level in the water may help, but the silicate is hardly here nor there. In freshwater tanks, the way to beat algae is stunningly simple: fast-growing plants. Hygrophila, Cabomba, hornwort, etc all work well. Slow-growing species like crypts and ferns have no effect. The theory is that fast-growing plants produce chemicals that suppress the growth of algae. In my experience, this method works well, even against Blue-green Algae.> The silicate test I use states that silicates are not an issue for freshwater tanks and will usually be between 4-20mg/l. If I go to R/O water, will decomposing plant material leach silicate back into the water anyway, and if so for how long? <Most plants contain very little silicon; the exception are grasses, which deliberately use silicone to prevent grazing (and this is why grass-grazing mammals have rapidly-growing teeth -- the silicon is constantly wearing them down). Hope this helps, Neale>

Re: BGA/silicate connection -- lesson learned 1/9/08 Hi Neale, <Scott,> I thought I'd update you on this exchange we had a couple of months ago. I tried everything from phosphate pads and powders to erythromycin, yet the black slime persisted. Finally, as an experiment, I did a series of 25% water changes over three days. The black slime is disappearing rapidly. Just goes to show you , even if your test kits are reading zero nitrates and phosphates, they may still be in your system and are just being consumed by the algae. <Indeed. Possibly something not directly measured... sulphate, iron, magnesium... who knows?> Also, I want to thank the crew for the information you've put together on Betta keeping. Because of your advice, I set up a 5-gallon tank, with a very small HOB filter and a heater keeping it at a steady 82F. The Betta is very active and happy, and full of personality -- more so than I have ever seen in any of those desktop/countertop bowls. <Precisely. While you *can* try and keep a Betta is a big brandy glass, if you're a little more generous, you'll get far more out of these fish.> Finally, a quick question. I am trying to advise a friend on setting up a 40-gal breeder for freshwater. With a tank this length, is there any advantage to using two heaters and two HOB filters to provide more consistent water conditions throughout the tank? <If finances allow, this approach can work very well. More circulation always results in better conditions in the aquarium, and though 4x the volume of the tank is a good minimum for community tropicals, 6x the volume is better, and for many fish even 10x the volume is good. It's a good idea to choose two under-powered heaters though. That way, if one fails in the "on" position, it won't have enough wattage to boil your fish. So if your tank needs 100 W of heating, use two 50 or 75 W heaters. FWIW, this is precisely how my community tank is run, with a heater and a filter at each end.> Thanks again, Scott <Cheers, Neale.>

Lace rock growth, likely BGA 5/2/07 Hey all! <Denise> After a quick search, I decided to just ask.... I have lace rock in a cichlid tank. After about 1 month, the rock has started growing a blackish film/'algae' type? growth? <Yes... likely Cyanobacteria...> I am in hopes it is not the beginning of the black beard type algae :( I did soak this batch in RO water for a few weeks and rinsed it well to remove sediment etc. I plan to add a phosphate hoping this will solve the problem. <Not likely limiting here... Often Lace Rock is a source itself...> I am wondering if this is common with lace rock? <Not uncommon> I have also used it in another aquarium with the same issue. <Do read here: http://www.wetwebmedia.com/FWSubWebIndex/fwbgafaqs.htm and the linked files above> Thanks! Denise BTW, once upon a time it was easier to find what we search for with the 'cached' option, this is not available any longer? Researching is no longer user friendly on this site <Do try the search tool here: http://www.wetwebmedia.com/WWMAdminSubWebIndex/question_page.htm Unfortunately, all others are not "cached" capable... Google Adsense doesn't offer such. Bob Fenner>

Massive algae bloom 12/3/06 Hello, I was wondering if you could help me with an algae problem. I have a green very slimy algae growing on almost everything, <Ahh, likely Cyanobacteria... Blue-Green (though the color is not definitive) "algae"> and I don't wont to resort to chemical means as I don't want to harm my plants. If I did go this route would the bulb of my dwarf lilies be affected to the point where if I cut all the leaves off that the plant couldn't regrow. any advice would be appreciated. thank you, CJ <Good that you understand the need to act here... Please give this article and the Related FAQs (linked at top) a going over: http://www.wetwebmedia.com/FWSubWebIndex/fwalgcontrol.htm Bob Fenner>

Ich and Salt - Thanks! And BGA FW situations - 11/02/06 Hi Robert, <Jason> Don't know if you remember but you answered some questions for me back in the early summer about curing ich with salt, and I'm happy to report that method worked flawlessly - haven't seen it since and didn't lose any fish to it. <Ah, good> Now I have another problem that I can't seem to find a satisfactory answer to after combing the internet and WetWebMedia over the last week. From what I've gathered, I believe the problem to be "Cyanobacteria" (blue-green "algae") - my plants, rocks, and driftwood have been overrun with a coating of black slime, and periodically I get patches of a very bluish color in the gravel (most visible when it occurs along the glass though I'm sure it's in the middle of the aquarium too). I guess my first question is - in your opinion does this sound like what it is? In some descriptions I read people describe it as a flaky substance - it's not flaky in my aquarium, in fact it's very hard to scrub off the hard substrate and impossible to remove from plant leaves without destroying them. <Does read like BGA> I do a 25% water change once per week where I vacuum the gravel (as I've always done before the problem), and as needed I remove leaves as they get taken over, and scrub rocks and wood periodically when it starts to coat a significant part of them, but it always comes back full-force within a few weeks. I also do not overfeed the tank - I feed once in day, a moderate amount they can eat quickly, and not every day - sometimes once or twice every two or three days (logic being in nature food comes and goes, it's not on a regular schedule). If it helps, my current stock is 3 swords, 2 platys, 4 Corys, and 2 small-medium angels in 37 gallons. The idea is the angels will feed on the fry of the livebearers to keep it in control (one of the swords is a small juvenile that was big enough to get away before the angels were added - haven't seen any fry since...[evil mad scientist laugh]. <Perhaps related> The sad thing is, after I cured the ich problem, and before this started, the plants started booming, and now that this has set in they are completely stifled. (Let me note here my ammonia/nitrite readings have been 0 since the tank cycled 5 months ago, and nitrate is low given the regular water changes.) In removing leaves, new ones don't come in fast enough and now the plants are losing ground to this instead of gaining, and I'm considering ripping them out. Here's another factor I learned about our water here, unfortunately after adding angelfish. Our tap water has a seemingly "unbreakable" pH of around 7.5. By that I mean I've come to realize that the "pH 7" products I used to add during water changes caused only a temporary drop, never lower than 7.2. After getting angels I tried giving up on those products and adding only "pH drop" products to try and bring it down closer to 7. That failed too (even after months, after the "balancers" from the "7.0" products had plenty of time to be flushed out), to the extent where adding even "massive" doses would not drop it past 7.2 and it would always rebound to around 7.4/7.5. <Mmm, this pH range should be fine for "domestic" angels... are quite flexible with many successive generations having been produced in captivity> By "massive doses" I mean if the recommended dose said add 1 tbsp/40 gallons and "more as needed", I could add 3 tbsp over a few days to my 37 gallon tank and could not break the 7.2 barrier. <Please read on WWM re... Such changes should be done outside the system, through water changes... Better to start with "cleaner" water... Reverse osmosis most commonly... mixed with some straight source water...> Since most of these products contain sulfuric acid and I don't know what kind of side effects the sulfur can have I abandoned that too. <Mmm... actually quite rare to have H2SO4 in commercial products in the States... too quick a proton donor...> I did lose a couple of angels early on I got from a major chain over this time but the second batch I got from the LPS have been hanging in there for a few months in the unaltered tap water pH and I'm leaving it that way for now (and won't buy any more if these die until I figure this out). I know a stable high pH is probably better for them than one that fluctuates. <Yes!> Anyway, that was a long way of saying - do you know if the water conditions I have are favoring the Cyanobacteria/black slime problem? (and secondarily, is it better to leave angels alone that are in a 7.5 pH and seemingly happy or...) <Mmm... well Cyano can/will proliferate given conditions that don't favor other photosynthetic life... An abundance of nutrients, too little intense lighting of useful wavelengths, poor circulation/aeration... These are covered on WWM as well.> Third and final question - I decided today to purchase a canister filter. After much debate and hearing extremes between people that live by the Eheim and people that knock the cheaper Fluval, I decided to go with the Filstar XP2 which most claim to be very reliable. Given my conditions, they offer media to soften water, and there are peat media out there (not Rena brand yet) that can be added to lower pH. <Again, reading... and starting with less solute laden water...> My question is, in your experience, do you think softening the water could potentially help with this Cyanobacteria problem I have? <Not the route I would go, no> If nothing else I hope it will make the water less stressful on the hardy angels that are still around. What about peat pellets as a two pronged question - could this help as well, and given how resistant I've described my water to pH lowering, can this help counter that significantly using a canister setup or if adding chemicals directly to the water doesn't help is it foolish to expect peat can help at all? < http://wetwebmedia.com/FWSubWebIndex/fwalgcontrol.htm and the linked files above> With the canister I'm going to take it easy and not attempt to change any parameters too much too fast of course (I'm going to leave my hang-on running too for a couple of weeks). For instance, their "softening" pack claims to lower "general hardness" but doesn't mention pH on the website, so I'm cautious that adding that plus peat could drastically change conditions. Thanks again for any help/advice, Jason <Keep reading my friend. Bob Fenner>

2-part question - pH and BG algae 10/2/06 I've read through the FAQs and researched other sites and find pieces of answers but nothing specific about dealing with my water conditions. Hope you're not too sick of dealing with these types of common questions but here it goes... <Hi there - this is Jorie. No worries, we are here to help and don't mind answering queries at all...otherwise we wouldn't do it!> My tank is about 5 months old, 37 gallons, fully cycled and stocked now with swords, angels, and Corys (4, 3, and 5). <Sounds nice.> It is heavily planted with "sword plants" and the lettucy stuff that grows out of control and which I thin (and am thinking of getting rid of). <Trying to think of what the second plant could be - does it grow from a bulb? Tall and thin? Aponogetons are quick growing bulb plants, and some produce wavy leaves that I suppose could be described as lettuce-like...> Once the tank was fully cycled, for about 2 months, the plants really thrived and boomed in growth, especially the sword plants which I like b/c they are attractive looking. Unfortunately, about 2 months ago a real problem started to develop with blue-green algae (Cyanobacteria). Started coating everything with a black slime, and the plants are obviously suffering from it. I've been doing a lot of physical removal (scrubbing rocks, wood, clipping leaves that are particularly bad) which has helped some but it's a losing battle. I regularly change 10 gallons per week out of the 37 gallon tank (from the day I set it up), but I fear that part of the problem is just that our tap water is dismal around here (Arlington, VA) for this kind of thing - lots of calcium carbonate and iron. I siphon filter my gravel every time I change water and for the most part the water I siphon is clear so there isn't a lot of debris on the bottom. <Phosphates are a usual culprit for algae growth - have you checked both your tap water and tank water for phosphates lately? I suspect you will find a very high reading. In the tank, I like to use PolyFilter filter media in addition to carbon to aid in phosphate removal. Also, as you pointed out, the tap water could be the problem...you may want to look into a RO/DI unit (reverse osmosis/de-ionized) - that will rid your source water of all the "nasties". Of course, it's a bit of an investment - I bought mine from www.airwaterice.com and I believe it was around $200 for a 3-stage unit. Alternatively, if you don't have other tanks, you could look at a cheaper alternative made Aquarium Pharmaceuticals (I think) - called a "Tap Water Filter". It's basically just a de-ionizing unit. It's around $30. You do have to replace cartridges in both types of units - in the RO/DI, about once per year; for the DI only, probably after about 30-50 gal. That's where the bigger RO/DI ends up paying for itself. If you go this route, be sure to remember to add back electrolytes and necessary trace elements, as well as add something to raise the pH from about 5.0, with appropriate products (I like Electro-Right and pH Adjust)> From what I've read, I think our tap water conditions are ideal for BG... <again, check phosphate levels> ...and I don't think increasing water changes is going to help much. <Sounds like you are already on top of water changes - keep up with what you are doing, but I agree, more likely won't help. Be sure not to overfeed your tank, and perhaps try giving the plants a "siesta period" for an hour or so without light.> I'm wondering if you have any advice. <See above.> While I'm fine with scrubbing stuff off of the physical decorations, that's not really feasible with the plants b/c the Swordplants grow extensive root mats, and to pull one up means uprooting everything and unless you trim the roots way back after you get them up, you'll never get them under the gravel again, and trimming the roots (I tried this on one plant) seems to cause a big dieback. <Yes, it is one thing to scrub rocks and such, but you really can't do this with plant leaves without damaging/killing them. If you find leaves that are completely covered with the algae you describe, do remove them at the stem with a scissors - the will eventually suck out the nutrients from the roots that the healthy leaves need.> The other thing I notice too though is that the black algae is starting to disappear in "blocky" patterns on some leaves, while it is taking over others (so no net gain), so I'm not sure if once a leaf gets coated it is a death sentence or if it can be reversed if the leaf continues to grow. <Not really - all you can do here is control the algae growth to begin with. I think if you get your phosphate levels under control and change your source water (the latter likely helping with the former substantially), you will see a *big* improvement. I don't see any information about your lighting conditions - if you have too much light, that can also cause algae growth. Also, direct sunlight on the tank will cause algae. A few additional things to think about...> Here's another clue about our water, and a second question I haven't found a good answer for. It seems to be loaded with calcium carbonates (or other substances that cause a high pH). Our pH is about 7.5 out of the tap, and it is extremely stubborn. I've tried "pH 7" products that will lower it very briefly then it goes right back even with multiple treatments. Then I decided that logically those products also contain buffers to raise it if it needs it, so since it's not lowering it, then it must only be adding to whatever buffer is already in the water that keeps it up as well. So then I started pH lowering products, and same thing - they will lower it to about 7.2 for a day or two, but it always creeps back up, and this is with multiple doses to the point where I'm afraid of taking it to far (seems these products tend to contain sulfuric acid, so I'm not sure what the sulfur content can to the fish if it gets too high). For example, it may say add one 1 and 1/2 tbsp per 40 gallons, and I can do that 3 times over several days and it won't drop past 7.2 and will still rebound. The amazing thing is that while my first batch of angel fish died that I got from Petco, the batch I got from my local pet store have been surviving well, seemingly very happily for awhile now in these conditions. I know this pH is too high for angelfish and when I discovered how bad this problem was I decided I wouldn't get any more but the angels I have now are alive and well. <I'm glad you are trying to provide ideal conditions for your fish, but in reality, a difference between a pH of 7.5 and 7.0 is not that bad. It is much more important to keep the pH stable, and by adding the various products you reference above, it seems as though you've got a good deal of fluctuation going on - that's bad. In all honesty, I'd say leave it alone. Fish are fairly adaptable, but do not tolerate changes in pH levels and the like. Keep in mind, also, that if you invest in either a RO/DI or DI unit, your water will come out at around 5.0 pH, and you'll have to add a chemical adjuster to raise it.> Anyway, I guess my second question is - is there anything you can do for water that refuses to drop in pH like mine (besides buying a mini-treatment plant to take out the alkalines?) Is it even worth putting in "pH drop" every week to keep it around 7.2 or can the sulfur or whatever side ingredients in these acids accumulate and cause harm themselves? <Again, you aren't dealing with a huge change (i.e., between 7.5 and 7.2), and I'd just leave well enough alone. Keep in stable and the fish will likely be OK. Save the money you spend on the chemicals for a nice RO/DI unit - I believe that is the best solution for both of your problems!> Back to my first question - does the pH problem (and underlying factors) have something to do with the blue-green algae problem? Again, the plants absolutely thrived for awhile so my gut is that they got big to a point where a balance was tipped and they started taking so much of something out of the water that let the BG algae thrive and now they're losing. <It's the "underlying factors" that are contributing...likely the phosphate in the source water.> Here's another site that is interesting and if it were correct it may suggest my problem may root in the fact my nitrates aren't high enough for the levels of phosphate in my aquarium: http://www.xs4all.nl/~buddendo/aquarium/redfield_eng.htm. Any experience with this? Since the fish don't seem to be suffering and it's an aesthetic problem I hesitate to tinker with the nitrogen levels. <I haven't seen that site before. It seems to be well researched, but if it were me, I'd start with just looking at the phosphate levels first. I was battling all sorts of algae, including blue/green and black beard in my freshwater planted tank, and once I switched to the RO/DI and added the PolyFilter, the problem virtually resolved itself. Oh, and one more thing - you say your tank is well-stocked with plants...that's very subjective, obviously. What I can tell you is that if you have so many nutrients for the algae to thrive on, you likely have room for additional plants - they will use those same nutrients, grow, and aid in starving out the algae.> Sorry for the long message but any help is appreciated - if you do choose to answer feel free to post on a FAQ on your site. Thanks and love your site. <I appreciate all the info. you provided me - helps me better diagnose a problem...no worries on the length of the question, my friend! You will receive a return e-mail, and we will be posting this answer on the daily FAQs as well...> Jason Arlington, VA <Jorie, Aurora, IL.>

Re: 2-part question - pH and BG algae: PART 2 10/03/06 Jorie, thanks so much, and I take it as good news that so many of my questions could possibly be addressed with a single solution - a RO/DI unit. I have heard of them vaguely so the advice is appreciated, I will look into it. As you say, $200 is not bad (especially if you only have to replace a cartridge once per year), and would easily pay for itself given that a "large" bottle of pH drop is $7-$10, and I'd rather take out the problem than just keep adding more chemicals. <Agreed. Do look at www.airwaterice.com - for the price, I don't think you'll find a better unit. And, their customer service is outstanding.> I know that you're right that stable pH is better than fluctuating pH, even if it's high. <Within certain limits, of course...> I'll be wary of the pH drop if I get a RO/DI unit, though I'd practically celebrate to see the pH of my water go below 7 - not that I want it to, just that I'm surprised our water is so pH resistant to anything I've tried. <LOL!> I do have one question - if the RO/DI unit will drop the pH around 5 and it's necessary to add something to keep it up, then won't the unit continue to remove whatever you add? In other words, will it be the reverse of my situation now where I'll have to keep adding a buffer to keep the pH up instead of down? 5 is pretty severe so that's definitely of more concern than 7.5. <If I understand your question, I believe the answer is that the RO/DI unit is attached to your faucet (i.e., source water), not the tank itself. So, the water is only filtered once in this way - I use a 5 gal. jug to collect the water after it has been filtered, then add 2 tsp. of ElectroRight, 1 tsp. of pH Adjust - I'm left with 5 gal. of water with a pH of precisely 7.0.> Anyway, the "lettucy plant" is Hygrophila difformis (maybe lettucy wasn't the best adjective) - an invasive out in nature that doesn't need much light, so it's no wonder it does well in tanks. <Hmmm, not familiar with this - I will look into it, though, perhaps it can live in my slightly brackish water tank where not much plant life survives...> I didn't seek it out - just got one batch in the variety I bought starting out figuring I'll see in time which do well and which don't in the light I have. It took over very quickly though, and there are more attractive plants I have that grow a bit more slowly so that's why I'm thinking of getting rid of it. It can look good in its own right, but you need to keep trimming the tops off, planting them, and discarding the lower parts. <I had the same problem with Aponogetons - they grow very readily under regular output lights, but require frequent trimming. Look into the various anubias plants - they don't require much light at all and are slow growing. Very low maintenance in this regard.> Lighting - I'm not a plantophile... <...love this word!> ...and just have the factory fluorescent hood, but one thing I liked about my corner model tank is that it came with a dual-bulb hood, so I think that is why some of the plants I have that I read are doomed to fail are actually doing quite well. <How many gallons did you say this tank is? I, too, have a 44 gal. "corner" tank - really a pentagon in shape. I found that I needed to upgrade to a power compact (PC) fixture, since the tank is so deep. Even so, I can only plant low-mid light plants...> Anyway, thanks again, and if I get an RO/DI unit I'll give you an update and let you know if it works against the BG problem. Jason <Hope I've helped - Jorie>

FW Cyano in a Service Acct. 7/6/06 I have a tank that I maintain that has really bad Cyano. It's a lightly planted 55g tank. It's got 260w of new (several months) PC lighting - Coralife, a new Eheim canister, a Maxi-1200 for flow, a few rosy barbs, a couple of angels and a few tetras. They replaced an older acrylic tank with a new glass one. When I put the new tank in I replaced most of their deco and all of the gravel. I did a 75% water change at that time as well. Since then I have been doing 50% water changes every two with RO/DI water every two weeks (for two months now), and manually (by hand) exporting all the really thick Cyano. I know my water is clean - I make it myself and use it in all my store tanks which stay pristine. They (the tank owners) swear up and down that they've cut back on their feeding, and they're using NLS pellets. <NLS we'll take as Pablo Tepoot's New Life Spectrum... a fairly "clean" food> For the life of me I can't figure out where it's even getting the nutrients to grow, but this Cyano is THICK, and I can't kick it. Nutrient control has always worked for me and I'm just baffled. Thanks for the input. Scott <Mmm... well... because you are in the trade, know what you're doing, and this BGA has been so persistent and dominant, I would likely remove the fish livestock and either "nuke" this system and all its gear with a bleach solution, or even go the Erythromycin/antibiotic route. If it were you/my home system, I would try massive water changes, adding some aggressive live plant/s (likely floating...), some source of alkaline earth material (to "feed" the vascular plant/s). Bob Fenner>

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