Considering that orandas can reach 10" (usually only 8" though), a 20 long doesn't really provide much wriggle room and your fish will likely be left stunted. I wouldn't go any less than 55 gallons (for two orandas - they should have a friend).
...To be honest, I was, but I wasn't seeing both sides of the story. I made a false accusation, and I'd like to apologise to @Lucy for that. It was unfair to say she was drafted from "heck" (sic) and many others were making some ridiculous claims about mods here.
I think both parties should...
I've ordered online once. Float the bag for 10-20 mins, but don't open it. Once they've floated, tip the bag into a bucket with a net in it (to catch the fish). Then dump the fish in the tank.
Try turning the thermostat down to 74F. All of those fish are more temperate and do need cooler water.
I'd say hornwort, but I just want to ask;
-What's your lighting like?
-Do you dose ferts/is the tank dirted?
This info is important because Excel is essentially liquid Co2. Co2 accelerates plant growth, which means the plants need more lighting and nutrients.
Hi, nice looking tanks. I wouldn't recommend getting less than 6 tetras. Personally, I think you'd be stretching it by adding tetras, but you could maybe add six of them. So:
3x Hara Jedoni (bottom feeders)
2x Platy (if you want to add tetras, be best to avoid getting the third one)