I have two 20 gal feeder tanks side by side in a window.
One is well filtered and so green I literally can see nothing. I just dip the net and hope for the best. It temporarily held a 4 inch Jaguar that I could only see if it was next to the glass.
The other has no mechanical filter of any kind. And has never had a real water change.
It houses dozens of growing Convicts, breeding Apple snails, a crayfish and an inch layer of duckweed that I scoop out by the handful to feed to a lizard.
It's not exactly crystal clear, but clearish. Heck, it might be crystal clear if I cleaned the glass. But I leave that for the snails.
She could use other plants to compete with the algae. Not so easy with gold fish, as they eat all the good stuff.
But duckweed protected by a floating container might help. It grows incredibly fast, doubling it's mass in days. It sucks up all the algae food. And goldfish would love to eat the harvest.
