Cyanobacteria growth

[Lady Friesian]

Hi,

My 5 gallon shrimp tank is becoming overgrown with cyanobactera (blue-green algae). I did a search and found out that Mustafa's shrimp apparently really like this stuff, but my 3 amanos don't seem to eat it. I have already tried changing out the old lights and reducing the fertilizer added for the plants. I do regular water changes and manually remove a lot of the stuff, but it keeps coming back. I don't feed them that much, either.

Since I have a lot of plants, do frequent water changes, and the only animals are three shrimp, the tank doesn't have a filter or aeration unit. Would adding an external filter help keep some of the excess algae away?
Is there anything I can do to make the algae more palatable to my shrimp? (salt and pepper, perhaps?)

Thanks!

[badflash]

Stop feeding them. Algae eaters won't eat algae if there are other foods for them. If you are dosing with phosphates, stop doing it. Cut back the number of hours you are using lights.

Fert dosing and too much light gives you algae.

[YuccaPatrol]

If you completely black-out the tank for 4 days, the cyanobacteria will be completely gone.

Wrap it with blankets or whatever it takes to ensure that absolutely NO light can get into the tank. No peeking either!

When you unveil it after the 4th night, there will be no blue-green algae anywhere.

[Lady Friesian]

Thanks for the advice! No more food for them...but I'll watch to be sure they're eating.

YuccaPatrol, will the blackout kill plants? I don't have anything too delicate, but would rather not kill them. Also, I don't want a bunch of rotting plants to harm my shrimps if they die. (right now, the light is on a 12/12 hour on/off schedule)

[Mustafa]

I did a search and found out that Mustafa's shrimp apparently really like this stuff, but my 3 amanos don't seem to eat it.

I have actually found out in the meantime that my shrimp only eat certain types cyanobacteria (there are many) but won't touch the nastiest types unless they have absolutely nothing else to eat, and even then they might not touch the really nasty ones. Plus, if the shrimp are in a tank that is infested they won't eat the cyanobacteria. No only that...they will die one by one since the cyanobacteria indicate that there is something severely wrong with your water parameters. Some sources also say that cyanobacteria can give off substances into the water that are poisonous in large amounts.

Even if the shrimp eat it, it won't make a dent at all. When I was feeding *certain* cyanos to my red cherries (long time ago) the cyanos came from a different tank and they were not the really nasty, thick carpet-building type. I hope this clarifies things. So, generally, after more experience, I do not recommend cyanobacteria as food as it will be far too difficult for the average person to distinguish between the types that shrimp eat and the types that they don't.

[YuccaPatrol]

YuccaPatrol, will the blackout kill plants? I don't have anything too delicate, but would rather not kill them. Also, I don't want a bunch of rotting plants to harm my shrimps if they die. (right now, the light is on a 12/12 hour on/off schedule)

I have done this several times with my larger fish tanks with great success. I keep mostly low-medium light plants with a LOT Java Fern and Anubias. Neither of these were ever affected by several days of darkness.

My guess is that in a 5 gallon tank, you do not have the most intense lighting that the planted tank people use for plants with a very high need for light.

If that is the case, your plants should be just fine and the 3-4 days of darkness without feeding will give your shrimp extra incentive to work on any algae they have been ignoring lately.

I will say that I am no plant expert, but I have success with crypts, Java Fern, Anubias, and a few others. If in doubt, you may want to ask some experts at a planted tank forum.

[Lady Friesian]

My guess is that in a 5 gallon tank, you do not have the most intense lighting that the planted tank people use for plants with a very high need for light.

I made my own fluorescent lighting setup, so I think it's pretty bright. None of my plants are very delicate, but they are used to a good amount of light. Should I still do this?

The algae is definately the kind they won't eat. It spreads in bright blue-green sheets over everything.

Do you think a filter would help, maybe after the light treatment? I don't want this stuff to come back!

[YuccaPatrol]

I was just reading about shipping plants on a planted tank forum and someone expressed concern that plants would be harmed while shipped inside a box for 4-5 days. The response was that nearly any plant survives the trip just fine.

So after reading that, I am convinced that just about any plant you have will not be affected at all.

I must say that when I have done the blackout, it has always been amazing to open the tank and see all of it absolutely gone.

I'll look forward to hearing how it goes with your tank.

What kind of light are you using? I have recently begun using the new compact fluorescent screw-in bulbs on my 10 gallon aquariums that originally had crummy incandescent tube bulbs. Makes a really big difference. If I ever get a smaller tank, I'll look for one that these bulbs will fit into.

[Lady Friesian]

Instead of a hood, I have one of those glass and plastic panes that fits over the tank. I bought two 28" fluorescent plant lights (18 watt) that came with a plastic fixture from a home improvement store. They are lying on top of my tank (plus they extend past it: good for small containers for breeding, land plants, etc.), and connect to a timer (both have separate cords, so I needed one of those adaptors you can plug several cords into).

The plants seem to like it, and the algae seems to really like it.

[Lady Friesian]

Well, the black-out did eliminate the algae...temporarily. It all grew back.

I think I know what the problem is, though. According to what I just read, the wattage of my lighting is over twice what I need for a planted tank of this size! That would account for the excess cyanobacteria and the crispy sagittarius...so that's why the parts at the surface are turning yellow!

[Sitting in the corner with a dunce cap]

[badflash]

There also needs to be a source of phosphates and nitrates. Light alone won't do it. Figure out where the nutrients are comming from and you can stop it.

[Mustafa]

I agree. It's not the light. There is a high organic load in your tank (even beyond nitrates and phosphates). Only solution...large frequent water changes in combination with removing the cyanos by hand until they are gone. Once the organic load is down the cyanos will stop spreading and you can remove the remainder by hand.

[Lady Friesian]

Could the bottomfeeder tablets (for omnivores) I'm giving the shrimp cause this nutrient excess? I break them into small pieces and watch the shrimp eat; it's usually all gone in around 15-20 minutes or earlier. Some dissolves, though. They also get pieces of spinach, but I doubt that's the problem.

[SilvrStar7]

I've found that Erythromycin works best for cyanobacteria, since it is in fact a bacteria. I don't believe this hurts inverts, at least that's what my pack insert says. I've used it on a tank with red claws in it, and they weren't hurt at all.
~Laura

[badflash]

I have used Erythromycin and it didn't kill the shrimp, but the algae just came back after the water change. My guess is that you are still overfeeding and not doing enough water changes. The bottom feeder stuff falls apart and goes down in the gravel. With only a 5 gallon tank you should not be feeding any more that about 1/4 of a tablet every other day of the bottom feeder food. I would switch over to something that has more plant matter in it too.

Get some sort of filtration going, or if you are using a foam filter, you may need to clean it more often.