3 Pcs Betta Fish Leaf Hammock, Betta Fish Practical Resting Spot Bettas Suction Cup Tank Decor Green Hammock Plant Leaf Pad Fishes Breeding Resting Bed for Fishes Aquarium Decoration Ornaments

no, tank mates is not reccomended for this small of a tank & you won't need any decor fin test: run pantyhose over it and if it catches or runs that's an unsafe texture for betta fins to add, he needs somewhere to hide in the dark (like a cave) and ideally somewhere to rest up near the surface. (they breathe air so they like to hang out in the top third of the tank) https://a.co/d/0ePV7SjI my guy loves this in the corner. ideally you want the filter on low flow. if at all possible. low current thruout the tank is best, the less ripples on the surface of the water the better. don't change your filter every 4 weeks like it says on the packaging, the nitrifying bacteria that change toxic ammonia from waste into safer nitrates live mostly within that media and on surfaces in the tank. you don't want to remove that bacteria it will crash your cycle. a lot more can be learned about this cycle depending on how sciencey you like it :) not explicitly necessary but helpfulhttps://a.co/d/0fR8JFEn excellent thermometers been working great for me for weeks now if you dont already have one. dont trust the stickers + they fail pretty fast. my betta hated the tank at 76 and much prefers 78 at minimum. but every fish is different some say theirs prefer diff temps https://a.co/d/0fhANhnd these help turn the water a yellowy color, which is good they come from rivers that arent perfectly clear and prefer tannins in the water for feeling secure. they're also helpful for stress and all that. honestly mine likes to lay down on them to nap and its nice to have a soft spot on the gravel.

while it does, maybe something he can rest in near the top because they really enjoy that portion of the tank. idk if ppl will flame me for suggesting something plastic, but mine really fucking loves this https://a.co/d/010ULtNW its his favorite spot, in the darkest corner just at the waterline so he can snooze. they dont have eyelids so a dark spot to rest is nice.while settling in, a couple days of low lights might be calming too

https://a.co/d/00XLwQa0 here is one great option for a quick improvement that my betta fish loves, he rests on this near the top of the water (so place this about a fish-height below the waterline) i placed this in the corner and this is the most beloved spot by my betta, who comes from a similar setup to yours. he was very tired from outswimming the high-flow filter and needed a lot of time to rest on this flat leaf, which he doesn't slide off of. of course, the A+ option would be floating live plants. look at facebook marketplace for local aquarists selling their excess plants!try turning the light off too, indefinitely while your fishie heals, as they prefer darkness to feel secure. i actually darkened the sides of my tank with black construction paper taped against the back, and two sides, because my betta was very stressed and noticed his reflection if i had the light on, leading to a lot of energy expended. the issue your betta is having is a lot more dire than these fixes, though. please follow the directions of the people who informed you about water conditions! the condition of the water is the #1 thing that impacts the bettas life and health.