About a year ago I purchased 20 goldfish that averaged 2 to 3 years in age. They are an average of 7 to 9 inches long at this time. They are in a 700 gallon tank. The tanks overflow is about 6.5’ high and runs into a waist high grow bed that is 4 feet wide and 20 feet long. The grow media is river rock about 3/4 inch in size. This system is large and not without its own troubles which I've been trying to address.
But the strangest observation was noticed today… I always have my 24’ long x 3’ wide sump (which is 2 feet in the ground) covered to keep the sun off the water. Half of it is covered with a metal cover while the other half is covered by floating rafts. I removed some of the metal covering this morning and noticed a 2” or 3” long gold fish in the sump! Where did that fish come from? The only fish I purchased (just over a year ago) were all at least 6” or larger. Even if the fish were reproducing it’s hard for me to believe an (uneaten) egg would have made it all the way through that 20’ gravel media and into the sump, hatched and then grew to that size in a year with nothing to eat but the roots of the plants in those rafts.
I’ve not moved all the rafts and metal covers to see if there were any more.
I’m sure it’s my lack of experience that has me stumped…
Very puzzling situation… any thoughts?
