None at all.
You'll find the fw hobbyists highly divided on this topic though. I do not use salt in any of my freshwater tanks at all.
Tropical fresh water. (Not salt water).
I'm assuming you have access to a fresh water crab because a Betta will not be able to live in salt water. The crab will attempt to catch and eat the slow moving Betta. It is only a matter of time before the Betta is killed.
Betta, goldfish.ex.
No. Bettas are true freshwater fish and do not require salt. Tonic salt for fish is usually sold as a substitute for keeping a healthy water chemistry and will ultimately harm the fish in the long term.
Aquarium conditioning salt at a level of about 0.20% is safe for your betta, so you can immediately put your fish back in the tank. If you think you may have put too much salt in, use a salinity test to check your tank and make adjustments if necessary before putting your betta back in.
You think probable to sodium chloride (NaCl).
Any kind of dead leaf rotting in the tank will poison the water and kill the fish. Maple leaves do not belong in a fishes water.
Some fish live in salt water because they just do. Some fish live in water because they were put in water. If you get a fish at home you can put it in salt or water. It also depends on there skin because the fish can have very sensitive skin and can only touch a certain kind of water
fake plants my fish loves them
First make sure if you put tap water in there you put water cleanser in there which can be bought at a pet store. Keep your betta in the bag and float it in the tank for 15 min. then without dumping the bag water in the tank use a net to move your betta to the tank.
put salt in the water
You need a de-chlorinating agent.