Oil Leak?

[livetodive]

My 47 gallon freshwater tank has a fine oily residue on it, but only at one end. There are also a few mineral deposits. We recently moved and actually found a few very small puddles of this substance. There are 3 fish in the tank; a blood parrot, a clown loach, and a small spotted catfish. Any idea what this substance is?

 

[QTOFFER]

Welcome to AA, livetodive!

Could you provide some more description? Photos?
Residue is inside or outside the tank? Were the puddles on the floor or tank stand?
What kind of filter are you using? Have you checked your water parameters (ammonia, nitrite, nitrate) and are the fish OK?

 

[loganj]

What kind of pump do you have? Is it a Rio by chance?

 

[lex]

Sometimes, when I put in too much topoff, the water level comes up and touches the bottom of the 'spill-over' on my HOT filter. And if I haven't cleaned the filter for a while, a film will develop on the surface of the water until I do a water change and drop the water level back down or clean the filter.