A Lunar Eclipse is when our blue/green globe saunters between the trusty moon and glowing sun, our planet completely blocks the luminous rays of the sun but the moon remains visible.
So, what exactly are those effects, you might ask? During the monthly new moon and full moon phases, all other factors being the same, you will catch more and bigger fish. This remains true for about 2 days on either side of the peak phases.
Now, the fishing magazines and sites around the Internet will have you believe that the relationship between solar/lunar cycles and fishing is much more complex than I have explained here. In reality it's not. In fact, if you try to follow most of the charts out there, you will find no direct correlation between those charts and the number and size of fish you catch.