Bubble Film After Tank Swap?

I recently downgraded my tank from a 30 gallon to a 20 gallon tall due to a leak but a few days after I got everything moved over I keep getting this bubble film in the top of my water. Could my filter be too strong? I have a Marineland 350 on it and the media was already fully cycled.




The tank is also bare bottom and was fully cleaned before I used it and all of my test came back fine.

 

That's caused by a lack of surface flow or something that is insoluble that settles on the top of your tank.

 

That's caused by a lack of surface flow or something that is insoluble that settles on the top of your tank.

The tank has plenty of surface agitation and flow it must have been something in the tank I'm going to start doing small daily water changes and see if it goes away.

 

The tank has plenty of surface agitation and flow it must have been something in the tank I'm going to start doing small daily water changes and see if it goes away.

It may possibly be protein from your food source, what are you feeding?

 

It may possibly be protein from your food source, what are you feeding?

I just have two small madtom catfish in the tank and I didn't feed them for the first two days to let them adjust and the film came before the first feeding.