"Dr Engelbert Buxbaum" wrote in message
...
dH wrote:

I have an established 55-gallon freshwater tank stocked with about 30
Lemon
Tetras, Blackskirts and Zebra Danios. A Magnum 350 and dual pad filter
take
care of the filtration.

Recently, a rainbow-hued 'essence' has appeared on the water top. The
bubbles keep it pushed away, but otherwise it covers the water.

The fish aren't stressed and continue to breed, the filters are cleaned,
10%
water change weekly, 25% monthly.

What could this multi-hued entity be?

Has anybody put their hand in the tank without washing first? Use any hand
lotion lately? Maybe it is some kind of oil.

dwhite