Biofilm on aquarium surface

[BleuTheBetta]

Hello. I just came into the room of my fishtank, about to do a 25% weekly water change, when I noticed a very thin layer of biofilm on the surface of my aquarium water.

What does this mean for my aquarium? Is it bad? How do I get rid of it, if I need to? Can this film hurt my fish?
Thanks for any answers in advance!!

 

[Archerfish]

How long has your tank been established? Reason I ask is it could be several things.
Some fish foods leave an 'oil slick' on the surface, especially if overfeeding.
Your hands and arms might have oil on them and transferring to the water. This is especially true in the winter when we tend to use hand lotion. Always rinse well before placing hands in the tank.
A new filter can release an oil slick.
Dead fish is a major cause of an oil slick. Carefully count or look for any dead fish and remove them immediately. Then test your water to see if the parameters are good.
I am sure there are other causes but one that rises to the surface (no pun intended) in the winter, with homes tightly closed, is airborne particulate such as Cigar smoke, cooking spray, hair spray, air fresheners etc. They can create an oil slick on your aquarium water's surface.

 

[Ichthys]

It won’t be a biofilm, just a film. The easiest way to get rid is to lay a sheet of paper on the surface, then lift it off by the middle.

 

[BleuTheBetta]

How long has your tank been established?

Around a month and a half. I like most beginners didn’t know about cycling when I started. I just finished my fish in cycle!

Some fish foods leave an 'oil slick' on the surface, especially if overfeeding.

I use Aqueon betta fish pebbles. I feed 2 pebbles 2x a day. I don’t notice a residue when feeding, though. I don’t know if I’m over feeding or not.

Your hands and arms might have oil on them and transferring to the water. This is especially true in the winter when we tend to use hand lotion. Always rinse well before placing hands in the tank.

Ooooh, that might be the cause!! I have had to toy around with some driftwood in there, and I can’t go a day without lotion. That might just be it. Thank you for the tip!!

A new filter can release an oil slick.

No new filter- this is the one that I cycled with. I guess you could call it semi new, it’s only around a month and a half old.

Dead fish is a major cause of an oil slick. Carefully count or look for any dead fish and remove them immediately. Then test your water to see if the parameters are good.

I have a single betta, no dead fish!

I am sure there are other causes but one that rises to the surface (no pun intended) in the winter, with homes tightly closed, is airborne particulate such as Cigar smoke, cooking spray, hair spray, air fresheners etc. They can create an oil slick on your aquarium water's surface.

Would a candle cause this? That’s the closet thing to your list that is in my room- I never use my hair soray and use butter for cooking
Over all, thank you!!! I will definitely keep all of these things in mind and watch for what nah be causing the film.

 

[BleuTheBetta]

It won’t be a biofilm, just a film. The easiest way to get rid is to lay a sheet of paper on the surface, then lift it off by the middle.

That helps a lot! Thanks for sharing that.

 

[BrianK]

You need some surface agitation, either from the filter or from an airstone.

 

[StevenF]

One of the most common causes of biofilm is bacterial growth on the surface of the water partially fueled by light. I also forms on natural ponds that don't get any human maintenance. Normally it is not a problem but if it gets thick enough it could impact gas exchange between the air and water. The best way to minimize its formations is increased water movement on the surface or to use a spray bar to spray water from the pump ? filter down onto the water surface.

 

[AdoraBelle Dearheart]

Ooooh, that might be the cause!! I have had to toy around with some driftwood in there, and I can’t go a day without lotion. That might just be it. Thank you for the tip!!

Be very very careful with this. Things like lotion, hand sanitiser, perfumes, anything else left on your hands and arms/whatever is going into the water can be highly toxic to fish. Always wash hands thoroughly before touching the tank or any fish stuff, I use Dawn dish soap and scrub down like a surgeon before I go near the tanks. Dish soap is good at removing oils and residue from things like that.

A good fishkeeping friend of mine - very talented and dedicated keeper and breeder went through a terrible experience because of contamination like this. She was usually so careful, but in the early days of covid, she lost almost all of her fish in a 55g tank due to bleeding on the brain. She was desperate to find out the cause and did everything she could to save the fish, but lost so many, in a horrible way.

It was because her small kid had been putting his fingers into the tank for the fish to nibble on, and he still had residue from hand sanitiser on his hands after returning home from shopping. That was all it took. Not even a lot of hand sanitiser, just the residue left on a tots hands, diluted into 55g of water, but still toxic enough to kill most of the stock.

I share that story not to alarm, but to make you and anyone reading this just how easy and potentially devastating comtamination can be. Never use glass cleaner on a tank either, just water and paper towel is enough to clean the outside of the glass, only use fish safe sponges etc to clean inside a tank, and be very careful with air freshener and other household cleaners in the same room as a tank. Bear in mind that something like air freshener sprayed in a room with a tank, even if particles don't land on the surface of the water, air is sucked into the filter and then into the tank, so it's better to avoid air freshener/aersol cleaners in the room with the tank.

I get a rare type of excema that mainly affects my hands, so I know the pain of dry hands, and that dish soap also strips the oils in our skin too, but I use non-perfumed/excema specific moisturisers once fish tank jobs are done, and at night before bed to replace the lost oils. Just takes some awareness and caution, be safe!

 

[BleuTheBetta]

Be very very careful with this. Things like lotion, hand sanitiser, perfumes, anything else left on your hands and arms/whatever is going into the water can be highly toxic to fish. Always wash hands thoroughly before touching the tank or any fish stuff, I use Dawn dish soap and scrub down like a surgeon before I go near the tanks. Dish soap is good at removing oils and residue from things like that.

A good fishkeeping friend of mine - very talented and dedicated keeper and breeder went through a terrible experience because of contamination like this. She was usually so careful, but in the early days of covid, she lost almost all of her fish in a 55g tank due to bleeding on the brain. She was desperate to find out the cause and did everything she could to save the fish, but lost so many, in a horrible way.

It was because her small kid had been putting his fingers into the tank for the fish to nibble on, and he still had residue from hand sanitiser on his hands after returning home from shopping. That was all it took. Not even a lot of hand sanitiser, just the residue left on a tots hands, diluted into 55g of water, but still toxic enough to kill most of the stock.

I share that story not to alarm, but to make you and anyone reading this just how easy and potentially devastating comtamination can be. Never use glass cleaner on a tank either, just water and paper towel is enough to clean the outside of the glass, only use fish safe sponges etc to clean inside a tank, and be very careful with air freshener and other household cleaners in the same room as a tank. Bear in mind that something like air freshener sprayed in a room with a tank, even if particles don't land on the surface of the water, air is sucked into the filter and then into the tank, so it's better to avoid air freshener/aersol cleaners in the room with the tank.

I get a rare type of excema that mainly affects my hands, so I know the pain of dry hands, and that dish soap also strips the oils in our skin too, but I use non-perfumed/excema specific moisturisers once fish tank jobs are done, and at night before bed to replace the lost oils. Just takes some awareness and caution, be safe!

Thank you, that is very great to know, I will 100% be wayyy more careful with my tank.
Thank you again!

 

[BleuTheBetta]

Where would I get a good airstone? Does anyone have a good link to one?

 

[Byron]

You have a filter, it would be easiest just to adjust it so it creates some surface disturbance. An airstone would have to be connected to an air pump, and it would not do as good a job in my view. Bettas like sluggish water so current should be minimal, but some surface disturbance will help.