oil slick

[stephenray75]

Okay i was looking at my tank and the surface looks like a oil slick. why does it do that? I do a 25% water change ever other week. My tank it 90gallons with 3 GTS and 2JD, 4 clown loaches, and a flounder. i do the changes every other week because I dont get any fluxuation in my parameter until the 3 or 4th week.
So my questions are agian...what causes the slick, and what can i do about it?

thanks for the info

stephen

 

[victimizati0n]

the slick is caused by uneaten food floating around.

Try to get more surface adgitation, and feed your fish less

 

[biogirl361]

i notice my tank like this when i take out the airstone, thereby reducing surface agitation to near nothing. try adding an airstone or something else to stir up your surface.

 

[cdawson]

It's not from uneaten food, it's from flake food or if you've recently put your arms in the tank or fed frozen foods.