skimmer to use with internal filter

[finfayce]

i have a PennPlax 600 internal filter in a 30 gallon tank. the fish in there eat frozen fish cubes. i get a film in that tank pretty soon after a water change. is there a skimmer that would work with an internal filter?

 

[Chuunofish]

I use a juwel skimmer which works well. Another idea is to defrost frozen food in tank water I use measuring cup, and drain before feeding, seems to remove alot of the oil.

 

[finfayce]

I use a juwel skimmer which works well. Another idea is to defrost frozen food in tank water I use measuring cup, and drain before feeding, seems to remove alot of the oil.

sounds like a good idea. thanks.
i did order a surface skimmer. i hope both ideas help.