Pineconing is a symptom, not a disease in itself. I'm going to offer several suggestions for you....
1) Pineconing: Use Epsom salt to reduce fluid retention.
I would not use aquarium salt right now. Salt causes fluid retention, which can make the pineconing worse. Instead, I would use Epsom salt.
Epsom salt (magnesium sulfate) reduces fluid retention and has a laxative effect (in people and fish). Since he is pineconing, I would use a variaton on OldFishLady's Epsom salt protocol. It starts out with a dosage of approx 1 teaspoon Epsom salt per gal on the first day, then brings it up to 3 teaspoons per gallon over the course of several days. The treatment can be done for 10-14 days.
OFL's Epsom salt treatment:
- Add 3 teaspoons Epsom salt to one gal of conditioned water.
- Stir/shake until the Epsom salt is completely dissolved.
- Using this premixed treatment water, make 25% water changes every 15 min for 1 hour today.
- Tomorrow, do a 50% water change using this premixed treatment water.
- The day after tomorrow, do another 50% water change using this premixed treatment water.
- Then, every other day for 10-14 days, do a 50% water change using this premixed treatment water.
Epsom salt is inexpensive, and you can get it at supermarkets and grocery stores. Look for 100% magnesium sulfate. (No dyes, perfumes or additives.) Since it doesn't contain sodium, it won't stress his kidneys (like aquarium salt does). Look for 100% magnesium sulfate. (No dyes, additives or perfumes.)
Also, feed small meals of high-quality high-protein foods.
Cover the top of the tank with plastic vegetable wrap. This will increase humidity levels, and make it easier to breathe. (It also has a calming effect.) Be sure to leave several inches of air between the water and wrap, so your fish can breathe!
2) Increase the Temperature:
70F is too cold for a betta. They're tropical fish, and do best at temps in the 77-84F range. When the water temp is so low, it lowers their metabolism, and it stresses their immune system which means they're more susceptible to health issues.
3) Next steps - Antibiotics
Since pineconing is just a symptom, you may need to treat the condition/disease that causes it. If the Epsom salt isn't effective in a day or so, let us know. It's possible that he may need an antibiotic that can act internally.
4) General observations/recommendations - Food:
Aqueon pellets are a decent food. But it contains a lot of grains/fillers, and some bettas become constipated and/or bloated on it.
If your betta has this problem, I'd advice switching to a higher-protein food, such as New Life Spectrum betta pellets or Omega One Betta Buffet pellets.
5) General observations/recommendations - Water Changes:
IMO, a 1 gal bowl is fine - as long as there are frequent water changes done. The recommended water change schedule for a 1 gal tank with no filter would be one 100% and two partial (about 50%) water changes per week. Frequent water changes are needed to keep the level of waste, toxins and ammonia low. If these are allowed to build up, well, it's like living in a toilet bowl!