Hi T tmandzik1 - did you say where you are?
To Fishman Dave 's thoughts on temperature: I've asked this question a few times & a few places, looking for the low-end occasional temp for various species (me: silver arowana). The only workable feedback we got was somebody (apologies, don't remember who) saying they had a couple of juv RTC in a balcony tank in Florida that spent winter nights ~55F through a couple of months and the fish didn't miss a beat. My expectation is that species from rivers that get a little altitude (>1500') will know these sorts of temperatures (Amazon/RioNegro, Guyana, Mekong, Eastern Congo, southern/eastern Nile), whereas stuff from lower/older islands & floodplain won't appreciate; IME clown loaches start getting timid at 25C get very quiet at 21C, for example, though I can't speak to where or how long until when health suffers.
So long as it's not particularly shallow with a dark (mud?) bottom, a pond that size isn't going to track pulses in air temp very closely unless there's a big rain. If the 50F is an occasional overnight, but back over 70F as the sun comes up (my house) then I'd not worry too much. Keep me/us posted either way.
I spotted him on 12/25 which was the last time I was there. I threw some food in and immediately came over to eat. I guess I’ll find out if he survived next time I’m there based on whether he appears to eat. Pond temperature should be significantly warmer than air temperature and more steady, however I am still worried based on members concerns. I will update you.This post was august of 2020 so I’m very curious to see if the arapaima is still alive being mid February! I think we often underestimate wild animals ability to survive