No, it's not bad for your garden. It's essentially distilled water, like the kind you used to use in steam irons. It's by nature "soft" water. It has no minerals like rainwater, so no nutritive value, but the plants in your garden can get that from the soil. It also has a pH of near neutral.

Hi there, yeah it definately won't harm your plants, but I'm not confident on the fish part of the question although my gut instinct is they should be fine too, as long as the water dripping from the AC unit is room temp??

Another way I conserve water in my house, is to collect all my rainwater from gutters and downpipes etc into a water butt. I have a ground level debris filter and rainwater diverter ('Gutter Mate'), which collects any organic matter - like leaves, moss etc, which I can put on my compost heap, and then diverts the rainwater to my water butt, for watering the plants etc.

I try to reuse & recycle as much as I can, and this diverter allows me to that in my garden too!