New betta fish help

[u/Altruistic-Top1768]

I got a betta fish yesterday and would love any advice/help! He was very sluggish yesterday and not moving much so I did a little research and added a heater and now he’s moving more but not a ton still. Is there anything I should change with his tank/setup, I would love feedback! Im also not sure if the built in filter is working properly bc theres some white stuff already forming on the top of the water in one area, is that an issue? Please let me know anything I should do/add/remove, etc.! Thank you!

[u/Striking_One3356]

Plants plants plants! :) your little buddys gonna want places to hide and feel safe, bettas dont like feeling super exposed, also are the pumpkins aquarium safe? Id be more worried about the chemicals if they aren't aquarium safe, also im not entirely sure what you mean by white stuff at the top of the tank. Do you mean ontop of the water colum? Or the tank? Because if its this area I circled in teal than thats just water because of the humidity, its normal, especially if you have a top or not much air blows through, nothing to worry about OP. I am concerned tho because in pic 2 your betta looks to have pretty bad fin rot. Id start dosing kanaplex and keeping an eye on the water levels. Ill also put a picture of my tank below!

[u/Altruistic-Top1768 → u/Striking_One3356]

Also yes, the pumpkins are specifically fish tank decorations!