Question: Oil, bubbles, and chunks????

[headFeed]

On the surface of my axolotl's tank, it looks oily and there's always these weird misshapen bubbles.
When I disturb the surface, the bubbles create chunks and float down.

I'm worried about this because my axolotl goes up to get air so he could be ingesting whatever this is.

I tested the parameters for Ammonia, nitrite, nitrate, and ph and everything is fine.
I'm thinking it's the filter because I don't have this problem with my fish/shrimp tank which has a hang on waterfall filter. That filter only has something called a bio bag that's just a mesh bag with charcoal.

The filter for my axolotl is a external canister filter that has carbon, some kind of "bio" that absorbs odors and provides a place for bacteria, and ceramic rings.
Pictures of the issue below, is this harmful, and how can I fix it without replacing the filter entirely??? Should I remove anything inside the filter?

 

[auntiejude]

This is biofilm. It's a mixture of shed slime coat, dead bacteria and dust, and settles on the surface when there isn't enough agitation. If you increase surface disruption with a bubbler or with the filter outlet it will stop it forming and allow the filter to filter it out.

 

[headFeed]

This is biofilm. It's a mixture of shed slime coat, dead bacteria and dust, and settles on the surface when there isn't enough agitation. If you increase surface disruption with a bubbler or with the filter outlet it will stop it forming and allow the filter to filter it out.

I guess I'll try changing the filter outtake to flute looking one. Thanks! I'll update later since I'm still suspicious of the filter.