Digital Aquarium Thermometer Fish Tank Thermometer Test with Large LCD Display Fahrenheit/Celsius(℉/℃) for Aquarium Reptile Terrarium Turtle Tank

there's not really different kinds idk. this is what i bought but I've seen different listings for more in one pack https://a.co/d/03zGlctQ i like this because i can detach it easily from my second tank to do the water change

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.