Internal Parasites?

[USNavyWife]

Housing
What size is your tank? 10 gallon
What temperature is your tank? 80 degrees F
Does your tank have a filter? yes
Does your tank have an air stone or other type of aeration? no
Is your tank heated? yes. top fin heater.
What tank mates does your betta fish live with? none

Food
What type of food do you feed your betta fish? Top Fin Bloodworms as an occasional treat and Aqueon Betta Pellets
How often do you feed your betta fish? 6 days a week. 3 pellets in the morning/1 blood worm (on occasion) or 4 pellets in the morning. 1 day of fasting.

Maintenance
How often do you perform a water change? weekly
What percentage of the water do you change when you perform a water change? At least 25%
What type of additives do you add to the water when you perform a water change? Aqueon Betta Bowl. I fill the gallon jugs with water and add the recommended treatment to each of the jugs.

Water Parameters:
Have you tested your water? If so, what are the following parameters?
Tested Today.
Ammonia: 0ppm
Nitrite: 0ppm
Nitrate: 0ppm
pH:7.2-7.6
Hardness: haven't gotten the test (couldn't find it here in Petco or Petsmart)
Alkalinity: ""

Symptoms and Treatment
How has your betta fish's appearance changed? He's really skinny. He's still recovering from biting his tail so his fins are rather tattered.
How has your betta fish's behavior changed? He darts away when you come near. As if he's frightened, but he's actually a really social fish and has never darted before. He also seems to be sleeping more than usual. Dinq has always been super active and swimming around and investigating what I'm doing for the day. I purposely put him in the dining room where my office is so he can be right in the action. He's also been hanging around the filter. I have it slightly baffled so it's not a powerful suction, but he seems to like letting his tail in there.
When did you start noticing the symptoms? Maybe about 1/2 a week ago. I didn't really notice him being skinny till I really looked at him today and his pictures from before.
Have you started treating your fish? If so, how? Not yet, hoping to get recommendations. I've read DarkMoon's post about using Epsom Salt, Jungle's Anti-Parasite Pellets, Jungle's Parasite Clear Fizz Tabs, and API General Cure. I wanted some recommendations as to which one would be more effective.
Does your fish have any history of being ill? Yes, back in March he recovered from SBD. He was really sick and close to dying, so possibly having a compromised immune system and traveling 3,000 miles with me to our new station allowed him to get sick?
How old is your fish (approximately)? I've had Dinq since January of this year.

** I haven't witnessed any stringy poo. I haven't seen anything suspicious, but I suspect with him being so skinny and darting and sleeping a lot more that something is up. He's just not acting like his normal self. I'm especially concerned about the weight loss.

Do you think it could be internal parasites?

[USNavyWife]

I've decided to start treating with API General Cure. Looks like my local petsmart was out of Jungle products, except for the pellets. I guess I'm better safe than sorry if it is internal parasites. I wouldn't want him to get any skinnier than he already is and I don't want them to progress. I'd hate to give him medicine he doesn't need if he isn't sick, but I can't think of any other explanation for this. Poor little Dinq.