Is Biofilm Dangerous?

[Picassoclown]

Hello everyone,

I have biofilm in my tank (215 gallon display, 55g refugium) that seems to be quite a bit. I just finished cycling, all levels are at 0, with the exception of nitrate (around 10PPM). I cleaned a lot of the biofilm out from the reugium today and I have my protein skimmer turned on and just added some macro-algae (pom-pom). I am going to spot clean the biofilm the best I can tomorrow off the rocks. My question is, is biofilm over time dangerous to the fish? I have no corals, I will be adding those after 6-8 months. Thanks everyone!

 

[Miami Reef]

Biofilm is not dangerous at all.

Is it green? Might just be film algae. Picture would help.

 

[Dan_P]

Hello everyone,

I have biofilm in my tank (215 gallon display, 55g refugium) that seems to be quite a bit. I just finished cycling, all levels are at 0, with the exception of nitrate (around 10PPM). I cleaned a lot of the biofilm out from the reugium today and I have my protein skimmer turned on and just added some macro-algae (pom-pom). I am going to spot clean the biofilm the best I can tomorrow off the rocks. My question is, is biofilm over time dangerous to the fish? I have no corals, I will be adding those after 6-8 months. Thanks everyone!

What does your biofilm look like?

 

[MaxTremors]

I would say it’s not dangerous, to the contrary it’s beneficial. Though I’d want to see what exactly you ‘re talking about. Also curious why you’re waiting 6-8 months for corals? Even if you’re going SPS dominant, there are plenty of species that will thrive way before the tank is fully mature.

 

[Picassoclown]

Hi everyone. Wow, thanks for the quick response! It is definitely biofilm, it's opaque, milky in color, and very slimy. It's stringy as well and its on the rocks and glass. It is definitely NOT green at all. As far as waiting 6-8 months. I just wanted to be patient and have Coraline algae growing and have a nice established tank up and running before I add some.

 

[Picassoclown]

I forgot to ask: Would trochus snails & hermit crabs eat the biofilm? Thanks in advance!

 

[Spare time]

BTW make sure to watch your phosphates if you are starting a refugium immediately (since you likely have very little phosphate)

 

[ReefLife_Guy]

I'm not an expert reefer but I wanted to chime in here because I do know quite a lot about bacterial biofilms. First is that biofilms are not at all a homogenous substance and vary depending on bacterial species and environment. It is not an accurate statement to say that "biofilms are not dangerous" because there are some biofilms that are beneficial and some that are harmful. For instance, we have beneficial bacterial biofilms in our gut that help keep beneficial bacteria alive but in some lung infections bacteria can produce biofilms that contain toxic molecules and that are impenetrable to antibiotics. Now what your are talking about here can be something benign in your tank or it could be something that you should definitely remove. I think some images will help identify better what you are talking about. More relevant to reefing, cyanobacteria produce biofilms that they live in and is why they are said to be "red slime" and I doubt anyone would say cyanobacteria biofilms are beneficial to your reef. There are also such things as algal biofilms which may or may not be harmful in your tank but like I said I think a picture would help people on here with similar experiences be able to say whether it has been good or bad in their tank. I had a small amount of white slimy film when I first cycled my tank and added a few fish, from what I remember looking up at that time there was suggestion that it was from heterotrophic bacteria. Beyond that I have no clue as mine did not return after I cleaned it off. Good Luck!

 

[Picassoclown]

Hey everyone. I have a few pictures. I just got home, sorry for not posting before. This looks like a biofilm/bacteria outbreak. Also, would snails and hermit crabs eat this stuff?

 

[Picassoclown]

I'm not an expert reefer but I wanted to chime in here because I do know quite a lot about bacterial biofilms. First is that biofilms are not at all a homogenous substance and vary depending on bacterial species and environment. It is not an accurate statement to say that "biofilms are not dangerous" because there are some biofilms that are beneficial and some that are harmful. For instance, we have beneficial bacterial biofilms in our gut that help keep beneficial bacteria alive but in some lung infections bacteria can produce biofilms that contain toxic molecules and that are impenetrable to antibiotics. Now what your are talking about here can be something benign in your tank or it could be something that you should definitely remove. I think some images will help identify better what you are talking about. More relevant to reefing, cyanobacteria produce biofilms that they live in and is why they are said to be "red slime" and I doubt anyone would say cyanobacteria biofilms are beneficial to your reef. There are also such things as algal biofilms which may or may not be harmful in your tank but like I said I think a picture would help people on here with similar experiences be able to say whether it has been good or bad in their tank. I had a small amount of white slimy film when I first cycled my tank and added a few fish, from what I remember looking up at that time there was suggestion that it was from heterotrophic bacteria. Beyond that I have no clue as mine did not return after I cleaned it off. Good Luck!

Is this biofilm?

 

[ReefLife_Guy]

Is this biofilm?

By the looks of your tank and absence of any visible nuisance algae, it is likely a product of some bacteria or fungal organism. You can call it a biofilm but like I said biofilm is a very broad term that is just describing a substance produced by organisms that is made up of a protein matrix which is why it is like a gel substance. Like others said, it is likely harmless but without culturing the substance or doing advanced molecular techniques on it, you will not know for sure what is contained within it and what produced it.

I think a healthy diversity of microbes and livestock is what helps the most with a successful reef tank. I agree with others on here, you are best off going ahead and adding your first fish (preferably a hardy fish like clownfish or pair of clownfish) as long as your water parameters are good and you are ready to start caring for livestock. I also think you should find a hardy beginner coral, like a soft coral to add to the tank. Addition of fish and corals, helps your tank to start building a healthy microbiome. When you start to see things like this slime, it is likely that you just have too much of a certain kind of bacteria in your tank. Since your tank looks like you started out relatively sterile, you will have to add inhabitants to start seeding your tank with different types of bacteria. Over time these bacterial populations will keep each other in check.

I trusted the advice of my LFS and have been successful thus far. They say that once you have completed a fishless cycle, you are ready right away to add a couple of hardy fish and corals. In their experience they never have issues once adding livestock and corals in a brand new tank that has been cycled in this way, as long as you don't go crazy and give the bacteria enough time to compensate for the additional bioload.

 

[ReefLife_Guy]

My advice would be to remove what you can, do a water change and add some fish. My guess is that this will go away over time as you add new livestock to the tank. I think where a lot of people go wrong is they worry about a problem so much and make a bunch of changes to try and fix it but end up making the problem worse.

 

[Picassoclown]

My advice would be to remove what you can, do a water change and add some fish. My guess is that this will go away over time as you add new livestock to the tank. I think where a lot of people go wrong is they worry about a problem so much and make a bunch of changes to try and fix it but end up making the problem worse.

Wow, thanks for the in-depth response Reeflife, I truly do appreciate it! I actually do have a few inhabitants in: 2 clownfish and 2 small hermit crabs. In 2 weeks I get 2 more hermits and 2 snails. End of the month I will be adding in a small school of damsels, or a firefish. I will also be doing some spot cleaning today and removing as much of this film as I can, along with adding new water from what I pull out. Thanks again!

 

[Picassoclown]

My advice would be to remove what you can, do a water change and add some fish. My guess is that this will go away over time as you add new livestock to the tank. I think where a lot of people go wrong is they worry about a problem so much and make a bunch of changes to try and fix it but end up making the problem worse.

Hi Reeflife,

I meant to ask you, if this biofilm continues to grow, would weekly water changes be too much for a brand new system with recently introduced inhabitants? Thank you in advance

 

[ReefLife_Guy]

Hi Reeflife,

I meant to ask you, if this biofilm continues to grow, would weekly water changes be too much for a brand new system with recently introduced inhabitants? Thank you in advance

I don’t think so, I started off doing 10% water changes weekly. I was under the impression that I could prevent ever having to deal with nuisance algae but I think it just delays the inevitable. I ended up going on vacation for 4 days and overfed a bunch with an automatic feeder and came back with green hair algae everywhere. Large water changes every week might be stressful to your fish and inverts especially if the chemistry is very different between the old and new water. Unless you have a reason to do more than 10%/week like lowering nitrates, fixing salinity, adjusting some other water parameter, etc. I wouldn’t do more than that. I also wouldn’t stress too much about trying to get rid of that slime unless it looks like it’s affecting the current inhabitants. Not sure of your setup exactly but good flow in the tank would help suspend some of that and allow it to be removed through whatever filtration you use. If this was my tank, my only concern would be that this slime becomes abundant enough and it covers the water surface reducing oxygen exchange with the water. The best way to make sure this doesn’t occur is just to make sure whatever flow method you are using is keeping the water surface agitated. Many anaerobic bacteria make biofilms because oxygen has a difficult time diffusing through it.

 

[Picassoclown]

I don’t think so, I started off doing 10% water changes weekly. I was under the impression that I could prevent ever having to deal with nuisance algae but I think it just delays the inevitable. I ended up going on vacation for 4 days and overfed a bunch with an automatic feeder and came back with green hair algae everywhere. Large water changes every week might be stressful to your fish and inverts especially if the chemistry is very different between the old and new water. Unless you have a reason to do more than 10%/week like lowering nitrates, fixing salinity, adjusting some other water parameter, etc. I wouldn’t do more than that. I also wouldn’t stress too much about trying to get rid of that slime unless it looks like it’s affecting the current inhabitants. Not sure of your setup exactly but good flow in the tank would help suspend some of that and allow it to be removed through whatever filtration you use. If this was my tank, my only concern would be that this slime becomes abundant enough and it covers the water surface reducing oxygen exchange with the water. The best way to make sure this doesn’t occur is just to make sure whatever flow method you are using is keeping the water surface agitated. Many anaerobic bacteria make biofilms because oxygen has a difficult time diffusing through it.

Thanks reeflife. Very informative as your previous advice! Moving forward with the next fish. Would you recommend adding a firefish, damsel, or anthias next? In addition, how far down the road would you wait before adding in copepods (I was going to start adding them around the 2 month mark since the clownfish were added)?