I started a 15 gallon container pond in my backyard several weeks ago. I have several types of hygro, ludwigia, anachris, java ferns, and sag planted in it with duckweed floating on top. It is under some small trees and tall plants outside with not a lot of direct sun except in the morning and then filtered sun and shade after. There is no filtration or powerheads. At first there was no mosquito larvae, which was surprising. However, a week ago they showed up en mass. To combat this I added six guppies. What surprised me was that after their initial crazed assault on the larvae they started swimming in a school, hunting the larvae. It reminded me of a pack of wolves. They did not school inside in their tank but they are doing it outside. Has anyone ever noticed this behavior? Just curious.
LOL. maybe it's the same principle behind feral dogs and cats? They get into the wild and make packs. All about survival now, no more living the high life that comes with living in an aquarium!