Betta Bowl Gone Wrong?

I have a 5 gal aquarium that I originally intended as a small aquarium for tetras, and wound up putting a betta in it. The first betta had a rainbow film on top of the water, got really bad fin rot and died in days. I investigated online and rinsed the aquarium really well and baked the rocks in the oven. When I reassembled the tank and dropped a new betta in, the film started back up again. The betta has been in there for about a month now, and he seems very happy, but I'm concerned about the film. When I dip a cup to remove it, it clumps up into a cloudy white chunk of slime. What is it, and what can I do about it?

Note: I have a moss ball, an anubias plant and a snail in with him.

 

Likely protein from the food.
Do you have a filter on the tank?
Surface agitation helps deal with the film.

 

Hello!

The rainbow film is called biofilm, and it from the buildup of protein from foods or other bio materials in the tank. It's harmless, but it cuts off oxygen supply, which is especially concerning since bettas do need oxygen from the surface as well as from the water. It happens when there isn't enough surface agitation it dissipate it. You can add a bubbler to help with said surface agitation and help dissolve the film. If your Betta isn't too keen on the bubbler, you can position it just near the surface so it doesn't disrupt too much of the general water column. For the most part however, you can start off with sopping it up with a chemical-free paper towel or using a cup to scoop it up.

Also, did you cycle your tank before adding your new Betta? And what kind of filter do you have?

Hope this helps and best of luck.

 

The tank has been going for about 2 years now, so I would hope it's cycled lol. But it never got that film with any of my other fish in it.
The filter is an Aqueon QuietFlow with a small cartridge.
I've just been scooping it by hand and doing that as my weekly water change, but I'm concerned doing that because my rocks aren't getting vacuumed.

 

I'd add a small sponge filter or airstone to help. There's also likely food debris in the gravel too if it isn't getting vacuumed, it'd definitely cause a protein layer to form.

 

The tank has been going for about 2 years now, so I would hope it's cycled lol. But it never got that film with any of my other fish in it.
The filter is an Aqueon QuietFlow with a small cartridge.
I've just been scooping it by hand and doing that as my weekly water change, but I'm concerned doing that because my rocks aren't getting vacuumed.

You may want to do a gravel vacuum. If your tank is cycled, then there is really no worry about doing a large water change for his benefit. There is a chance that depending on what your feeding him, some of the rotting food in the gravel is helping to contribute to the protein buildup. Tbh, it's not the best to only clean the film once a week, it builds up and cuts off oxygen supply. Just try to add a little more surface agitation and the problem should (hopefully) go away

 

You can use paper towel to take the biofilm off. Frequent water changes help too.

 

You may want to do a gravel vacuum. If your tank is cycled, then there is really no worry about doing a large water change for his benefit. There is a chance that depending on what your feeding him, some of the rotting food in the gravel is helping to contribute to the protein buildup. Tbh, it's not the best to only clean the film once a week, it builds up and cuts off oxygen supply. Just try to add a little more surface agitation and the problem should (hopefully) go away

I will definitely add some more surface agitation. Thank you!