Water conditioner is a must (anything that gets rid of chlorine and heavy medals), Melafix is always handy to have as a handy cure-all, freshwater aquarium salt, and food (Hikari Betta Bio Gold seems to be the resident favorite of most here, including myself
) and some freeze dried blood worms for a treat to give him one or two once or twice a week as a treat. If you have a dollar store or craft store near you you can buy a bag or two of colored glass stones, marbles, or river rock for the tank instead of just gravel if you like, just make sure whatever you buy you wash it really well in very hot water. Also, I wouldn't recommend sand as your substrate (stuff for the tank floor), as it can be difficult to clean if you're not used to it and with such frequent water changes (once a week at least for a 2 gallon bowl) it'll just be a pain. A thermometer to keep track of the water temp. Finally, a small terracotta pot or some other small, opaque cave like place for a nice hiding spot when he feels like it. That should cover it, GOOD LUCK AND WELCOME TO THE FORUM!
from Drs. Steve and Foster's website:
MelaFix
Contains the natural botanical extract from the Tea Tree (Melaleuca, an excellent alternative to resistant strains of bacteria that are unaffected by traditional medications. Treats bacterial infections such as red ulcers, fin and tail rot, cloudy eyes, mouth fungus, and others in as little as 4 days. Also heals open wounds, ulcers, and damaged fins. Doesn't affect pH; safe for invertebrates. 8 oz doses 480 gallons of marine or freshwater. 64 oz is a concentrated formula and doses 19,000 gallons.
*For this be sure to only use 10 drops per gallon as bettas are sensitive to it. You can get a dropper at the pet store, a pharmacy, or even an arts and crafts store.*
Freshwater Aquarium Salt
All natural Freshwater Aquarium Salt serves as a general tonic and stress reducer for freshwater fish. During disease and stress, healthy gill function of fish is disturbed. This can lead to the loss of electrolytes through the gills (sometimes called osmotic shock), reducing the intake of oxygen and release of carbon dioxide. Freshwater Aquarium Salt replenishes natural electrolytes and promotes healthy gill function. Temporarily blocks the toxic effects of nitrite to freshwater fish until water quality improves. Made from evaporated sea water – contains no artificial additives, sugar, or artificial color and will not change pH. Use Aquarium Salt with tropical fish, goldfish, and koi but should not be used as a substitute for marine aquarium salt.
*I recommend you use 1/2 teaspoon per gallon for bettas.*
Amunet beat me to the punch. LOL