Also, heres some more info i really want to share if ypu choose a betta!!! You seen to be really worried about your fish being stressed or developing a disease. As long as you do your water changes you really shouldnt see much illness. Doing too many frequent water changes can stress your fish, and all you need is to subside a little bit and only do scheduled water changes. If they seem really stressed about their new home, Indian Almond leaf tannins and Oak leaf tannins help relieve them of stress! The biggest disease I see people post about on betta forums in finrot. Its treatable with clean water and a little bit of aquarium salt! Clamped fins are another scare, but clamped fins are usually a side effect of cold watertemperatures or stress. Bettas also will produce (both male and female) horizontal pale lines. This is normal when you first bring fishie home OR if you need to take out the fish to do a full water change. If you overfeed your fish and he/she hasnt pooped in a while, they can get constipated. For constipation, a pinch of epsom salt or even a drop of PURE aloe vera (noooot the kind for sunburns!) into the water can help as a natural laxative. Dont overfeed- they can easily die this way! About 5 pellets a day are enough without going overboard, with an occasional treat of a bloodworm after supper is fine too.
Also substrate and certain decorations can cause diease!! My hubby lost his first betta to this. Avoid any of those bright colored dyed aquarium rocks!!!! The chemicals of those, even if you rinse em' good, can kill your fish. We also bought a volcano from Walmart and the chemicals leaching off it in the warm tropical water probably didnt help either. Not all commercial decorations are actually 'aquarium safe'! Stick to smoothed freshwater rocks, certain woods that can release helpful tannins, and live plants. With decorations make sure that they wont injure your fish!! If it snags/catches on panny hose- its not sutible for an aquarium. For substrate I perfer finely ground sand or natural river rocks that are too big for your betta to swallow. Large-grain sand can easily kill your fish, thats why I say finely ground. Bettas love to poke around with their mouths at the sand for dropped pellets or food, they can accidently swallow rocks, gravel, and sands. I wouls also avoid large chunks of limestone as it masses with the water Ph, makes the water too neutral for bettas. For sand substrate, you will need to rinse it a bit so the water isnt cloudy. Let it settle before introducing your fish so he/she isnt breathing in sand particles into their lungs LOL.
You dont need copper unless you have a serious parasite emergency- it doesnt really come out of the tank either. Ever. You also dont need charcoal filters unless you need to remove fish medicine from the water.
Keep your tank clean and give them plenty of space to breathe and you shouldnt have many problems at all!
If you get live plants and they have snails (trust me.... you will know after a week of introducing your plants to the aquarium!) they should be fine, your betta might eat them though LOL. Be careful of wild plants- dont ever pull plants from a natural pond into your aquarium as it can contan harmful parasites! Buy only plants from aquarium store specifically grown for decprative aquariums. Betta bulbs are easy and grow fast!
Hope this info helps, I hope you choose a betta as a fishie friend!!!!
Of course, make sure you set up the tank first before you buy a fishie whatever one you choooose!