Siamese fighters usually kept in small jars by people who have too many to house properly - breeders and pet stores. It really is suitable only for a short time.
You can only have one male fighter per tank and you must choose tank mates very carefully as fighters are easily stressed. Tiger barbs, for instance tend to bully and fin bite unless kept as a fairly large shoal.
Gourami's do well with fighters but need a decent size tank for several fish.
The best advice I can give is to ask at your local pet stores about tank conditions/mates, see what store is happy to advise and are not just after your money and stick with them. Good luck, once you start you will be hooked for ever!