Q&A: We have a 3gallon pico reef, want a pico fresh/brackish as well..?

Question by Bluebear: We have a 3gallon pico reef, want a pico fresh/brackish as well..? We want to feature a uncommon fish in a planted environment and are open to ideas. We’ve considered butterflyfish, leaf-fish, a puffer, anableps (get too big!) and killies. Keep in mind this is a 3gallon tank. Best...