Betta darting around; I'm concerned

Hi everyone; I'm a newbie who has done hours, no days, of research since receiving my betta as an unexpected gift two months ago.

A few days ago, Boomer had a whitish speck on his tail; it’s gone but now he has a small whitish bump under his mouth. Today he started darting more often than normal; he’ll be swimming along then dart, like he’s having a spasm. Also today noticed his bottom fin is a bit shredded with some small holes (does not appear to be rotting though). It’s possible water intake caught him but perhaps it’s from brushing against his cave ornament. He does appear to be brushing against plants more often than usual.

Here are my stats:

NitrAte: 20
NitrIte: 0
Hardness GH: 150-300
Alkalinity KH: 120-180
PH: 7.8
Temp: normally 80-82
5 gal tank set up: 9 July 2005, Cycled 20 August
Water: treat combo tap/RO from lfs w/Aquasafe
Lighting: T5 8W fluorescent (on about 12 hours/day)
About 1” gravel

Weekly: vacuum surface of gravel, change out about 1g of water (20%)

Daily Feed: 4-6 hikari or similar pellets or 2-3 freeze-dried bloodworms, part of a pea once per week (little to no waste) top off water from evaporation

At the time cycled, had outbreak of planaria. I reduced feedings to current feeding schedule (I had been feeding 2x per day) and the little critters died off.

Brown algae (diatoms) also appeared around the time tank cycled; started out yellowy looking and I thought it might be the beneficial bacteria. Gradually turned to darker rust color, in clusters, more of it, and seems to be visible only on surfaces receiving direct light (none visible on the backside of a light colored gray and white decoration), including front surface of tank.

A week ago added anacharis, moneywort, and mondo grass; also added some laterite into gravel (even though I rinsed the laterite water had reddish cloud for about a day). Now have some short hairy looking, white algae at the base of some of the anacharis.

1) What can I do to help Boomer? I’ve read about raising water temp and adding aquarium salt if it’s ich . . .
2) Should I be concerned about the brown algae/diatoms since it appeared a month ago?
3) Should I be concerned about the hair-like algae on the plants?

Thank you in advance for your help; I adore this little guy and I really want to help him.

Thanks Jaylin . . . I see that I didn't mention what I'd done so far for the brown algae and when I'd done the last tank maint . . .

The stuff cleans off really easy; I did a more thorough gravel vacuuming about two weeks ago after using an algae scraper on the tank walls. The last water change was Saturday, I used the scraper again, lightly vacuumed the surface of as much of the gravel as I could reach around the plants, which took out about a gallon of the water. I then took out his cave ornament and cleaned that off (using water from prev cleaning). I can deal with the ugly brownness as long as it's not harming him. It's not, is it? It's on the new anacharis too but the other plants don't seem to have any visible.

It has been a real challenge keeping his temp stable; small tank in Arizona home where room temp fluctuates a few degrees. I've been using a small fan to help cool him during the day.

Does it sound like he has ich, with it being just one spot? (it looks somewhat bigger than a grain of salt but not sure if that's because of distortion).

Unfortunately I did not have a thorough understanding of the cycling process at the time I put him in his new 5 gal home (thanks to crappy advise from Petsmart); cycling the tank with him may have weakened him somewhat

I've read so much conflicting info about salt and Melafix. I'd dosed with MF in the past (he got himself stuck in a hole and scraped his back a bit). He had some small holes in his fin then but those didn't seem to heal until after tank had cycled. How much aquarium salt is advised?

Any thoughts on what's wrong with him?
Again, I greatly appreciate the help anyone can lend!

I thought your idea of 50% water change and adding salt was a good one; I did that this morning, using 1/2 T of aquarium salt. I also turned off his fan and closed the lid to help raise the temp a few degrees; I'd read that at 86 parasites will die off. I've been at school all day so haven't had a chance to check in on him yet. I did notice this morning some small white particles in the water . . . possible that's part of the ich cycle??

I did use MF on him once; he was playing WCIF and got himself wedged into one of the holes in his cave that I never imagined he would try to fit through fortunately he came out of it with just two scrapes on his back so I treated with MF for one week and I think it helped him heal. He had some small holes in his bottom fin but MF didn't seem to help those; they finally healed after his tank cycled.

EDIT: The small hole is now blocked!

On a side note, I bought a heater for him awhile back but have had no reason to use it yet The coolest the house gets during winter is 70 because of the five parrots I am also sharing life with.

I have tried to post pictures in the past with no luck; plus pictures of him don't come out well (another think I need to research in my leisure time, which I have very little of these days).

I am concerned about the holes in his lower fin--not sure if all these pieces are related or not. Very frustrating. I asked him this morning to tell me what's happening but of course that didn't work out well :thud:

A fungus?? I appreciate learning from your betta experience btw