Erythromycin safe to use on healthy Discus and kill algae?

[discusmatt20]

Having a bit of a problem combating Blue-Green slime algae as of lately, and I remembered in the past dosing Erythromycin (or a similar medication with Erythromycin in it) when I had a sick discus and blue green algae, and the medication killed off all traces of the algae. With me getting tired of manually removing this stuff, was wondering if it would be safe to just dose the tank with Erythromycin in attempt to kill the algae off again even though my big discus is not sick? Never dosed a tank with medication with no sick fish lol. Any input would be great, thanks!

[AquaticNerd]

I wouldn't risk it since Erythromycin also affects your biological filtration.

I would consider other alternatives to combating the algae - Is the tank near natural sunlight? How long are the lights on? What's the water change schedule like (algae likes nitrates)?

[discusmatt20]

I wouldn't risk it since Erythromycin also affects your biological filtration.

I would consider other alternatives to combating the algae - Is the tank near natural sunlight? How long are the lights on? What's the water change schedule like (algae likes nitrates)?

So you think using that medication could be risky on my healthy discus due to its affects on my biological filtration?
Ive been trying to combat it via water changes and manual removal but as soon as I clear out most if not all I can find, within a couple days it starts to grow back. There is a window a couple feet to the left of the tank but the sun never shines directly on/at it. Increased my water changes the last couple weeks by doing 2-3 smaller WC's a week (mainly sucking up the algae). Nitrates are 0 but I do feed frozen beef heart daily and BW's once in a while. Thinking this may play a role but having a hard time switching to dry foods because this discus has been eating these frozens for years.
Was also debating getting a UV sterilizer? Not sure if that would help or what the best option is here. The tank used to be super heavily planted and the blue green algae whipped out 90% of my plants and continue to grow back lol. When I used that medication and killed off the algae, it didn't grow back at that time.

[smsimcik]

Blue green slime algae is not actually algae but bacteria (cyanobacteria). Yes Erythromycin will kill some of it, but it will eventually grow back if you don't address the underlying causes. Namely, excess nutrients like nitrates and phosphates. Particularly phosphates.
I doubt your nitrates are 0. A healthy system will have at least 5-10ppm at the very least. I suspect your test kit is not accurate. How old is it? You also need to test your tap water for phosphates. Some municipal water supplies are very high in phosphates. You need to find out if that could be a source of your problem.
Excess light can be a cause. Low oxygen levels can also be a cause.
A combination of all those things could be the cause.

You will need to do larger, more frequent water changes. Like 50% every other day for a while, sucking out as much of the slime as you can each time. Remove any dead plant leaves, uneaten food, etc.
It would also help to turn off your light for a few days until you can see a reduction in the amount of slime.
If you don't have an airstone or some other type of aeration, you need to get something going to raise the oxygen levels in the tank. Cyanobacteria loves low oxygen.

I know all of this because I dealt with the same problem several years ago in one of my large planted tanks. I too tried Erythromycin but it didn't work long term.

[discusmatt20]

Blue green slime algae is not actually algae but bacteria (cyanobacteria). Yes Erythromycin will kill some of it, but it will eventually grow back if you don't address the underlying causes. Namely, excess nutrients like nitrates and phosphates. Particularly phosphates.
I doubt your nitrates are 0. A healthy system will have at least 5-10ppm at the very least. I suspect your test kit is not accurate. How old is it? You also need to test your tap water for phosphates. Some municipal water supplies are very high in phosphates. You need to find out if that could be a source of your problem.
Excess light can be a cause. Low oxygen levels can also be a cause.
A combination of all those things could be the cause.

You will need to do larger, more frequent water changes. Like 50% every other day for a while, sucking out as much of the slime as you can each time. Remove any dead plant leaves, uneaten food, etc.
It would also help to turn off your light for a few days until you can see a reduction in the amount of slime.
If you don't have an airstone or some other type of aeration, you need to get something going to raise the oxygen levels in the tank. Cyanobacteria loves low oxygen.

I know all of this because I dealt with the same problem several years ago in one of my large planted tanks. I too tried Erythromycin but it didn't work long term.

Been using the API Master Test kit for years, the current one I have is no more than a year old and when I tested the Nitrates is was pretty yellow, maybe a little orange but certainly very low. I did not test for Phosphates however, so I'll test that and see where its at! I'll keep up the frequent water changes but maybe increase the % of water Im taking out for the next week or so.
I didnt want to turn off the lights due to plants still being in there, was planning to add more plants to help combat the algae and absorb excess nutrients. Got the lights running at 6 hours a day atm, maybe I'll decrease the hours each day?
I also added a large air stone last week as initially I thought this was due to lack of water flow/oxygen.

Anyone use the product UltraLife, Blue-Green slime remover? Just ordered on Amazon as it seemed legit but never used it before and not too sure if it has any risks or side affects?

[captainandy]

How often are you changing water? This is one of the best ways to lower any nutrient or micronutrient

Never dealt with FW cyano but constant battle in my reef tanks. Despite low nitrates and phosphates I had to treat every few months

The erythro will not do much damage to the bacterial filtration in the tank. With marine applications, the erythro was a one shot deal. Also, a major contributor is light intensity so you might also want to cut back on hours per day of lighting

[smsimcik]

Been using the API Master Test kit for years, the current one I have is no more than a year old and when I tested the Nitrates is was pretty yellow, maybe a little orange but certainly very low. I did not test for Phosphates however, so I'll test that and see where its at! I'll keep up the frequent water changes but maybe increase the % of water Im taking out for the next week or so.
I didnt want to turn off the lights due to plants still being in there, was planning to add more plants to help combat the algae and absorb excess nutrients. Got the lights running at 6 hours a day atm, maybe I'll decrease the hours each day?
I also added a large air stone last week as initially I thought this was due to lack of water flow/oxygen.

Anyone use the product UltraLife, Blue-Green slime remover? Just ordered on Amazon as it seemed legit but never used it before and not too sure if it has any risks or side affects?

I think I did use Ultralife Blue Green algae remover too now that you mention it. It doesn't contain any Erythromycin. I think it took 3-4 days but it did seem to eventually reduce the slime. I still think I had to continue the frequent water changes for a while. It also seemed to help once I eventually turned the lights back on and added more plants to compete with the algae.
Sounds like you're on the right track.

[bluelagoon]

I have always done a 3 day black out to starve the algae inside the bacteria and has worked a few times for me. Wrap your tank with a blanket and don't let any light at all in. Sometimes I get it when the summer months begin. All the causes are mentioned.

[pablos]

There are thousands different Cyanobacteria, some are very interested green in colours some are more like dark dust. I’m lucky to have few variants in my tank.

In my previous tank I had green coat on half of substrate. It started very slowly in one place then expanded quickly. The grow ratio was linear to number of water changes - more I do, faster they grow. I think it’s because each water change moved NO3 to very low level. Finally the turning lights helped there.

In the current tank I tried to combat them by addressing nutrients level, as someone mentioned before. It didn’t move it back, but they are growing slower after I removing them manually.

I was reading that Erythromycin might be a great tool to combat them, but I had similar concerns: healthy fish, bacteria in filter.

Today I applied hydrogen peroxide in affected places ... it seems working, but hard to say for how long.