I moved the whole system to a better, more sunny place. It was where the table is and behind the kitchen door. I also removed the biggest strawberry plant so the others get more nutrients. I really want the weed to grow now it's finally warm.
Every Saturday I go get one or two buckets of water from the park with duck weed, the fish love it and there is some bonus little animals to hunt. I add it to where I store the rain water, where the mosquitos lay their eggs. This way I can always feed them some algaes and there is often some mosquito larvae too (besides the usual dry fish food). Balanced diet 8-)
I'm germing a new seed: Auto Moby Dick from Dinafem. (Edit 2 days later: now a picture)