Fin rot, Melafix causing problems

[Behati]

One of my bettas died due to columnaris, and I feared it would be transmitted to the other one (since I unknowingly shared supplies between the two). I added a few drops of Melafix and Primafix to each fish's container as the Pet Smart guy said since the amount I should add adjusted for my container size (~600ml and ~400ml). Unfortunately the fish with columnaris died and soon the other one started acting sick. Not eating and it seems like slight fin rot (the edges are black). Once I immediately changed the water, the remaining betta perked up and it dawned on me that my previously perfectly healthy betta may be having problems with the medication.

Now that I figured out what's wrong with him, he's still not eating. He tries, then he spits it back out. He's been on a hunger strike for 2 days. I'm a bit concerned even though they can go without eating for 7 days.

Housing
What size is your tank? 2.5 Gallons
What temperature is your tank? 78F
Does your tank have a filter? No
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? He lives alone.

Food
What type of food do you feed your betta fish? HBH Betta Pellets
How often do you feed your betta fish? 2 times a day, max 4 per feeding but I'll take out the food if they don't eat it within 3 minutes.

Maintenance
How often do you perform a water change? Everyday so far.
What percentage of the water do you change when you perform a water change? Initially when I brought him home, 50% changes - now it's 100%.
What type of additives do you add to the water when you perform a water change? Aqueon Betta Bowl+, API Stress Zyme+

Symptoms and Treatment
How has your betta fish's appearance changed? The yellow coloring he had grew darker. He keeps his tail fin clamped tight (but not as much now that I took him out of the medicated water).
How has your betta fish's behavior changed? He went from not moving, staying at the bottom, flinching when trying to breathe air, to calmly swimming around although still not moving much in the new water.
When did you start noticing the symptoms? I noticed it once I put in the Melafix and Primafix as a precaution.
Have you started treating your fish? If so, how? I took him out of the laced waters.
Does your fish have any history of being ill? He's spankin' new. So I don't know.
How old is your fish (approximately)? I've had him for a week, but he looks young. He's a halfmoon though his tail isn't fully developed.

My problem now is if there will be any lingering adverse effects with the medication and how to get him to eat again. I only jumped to use primafix and melafix because the forum noted that it was a trusty medication.

[Sakura8]

It's a good thing you took him out of the water. Melafix and Bettafix both are not good medications for bettas. They have an ingredient called Tea Tree Oil that can potentially harm a betta's labyrinth organ, the organ they use to breathe air from the surface. It's crazy that they market Bettafix for bettas when it can harm them. Right now the best thing you can do for your guy is keep him in clean, non-medicated water until you see him improve. If he hasn't perked back up and started eating within a day or two, add 1 tsp of aquarium salt per gallon to his tank.

It sounds like you are actually probably feeding too much, also. Your guy only needs a little food so you may want to consider cutting back to 4 pellets a day MAX (so feed 2 at each feeding). I'm worried if you continue feeding him that many pellets he may bloat up and get constipated. Not good. I know it's really hard to resist the wiggle dance and the "feed me" eyes but for his sake, you've got to be firm and tell him only 4 pellets a day.

Also, you don't need to use the Stress Zyme. It's a nitrogen cycle booster, meaning it adds in bacteria that jumpstarts the nitrogen cycle you get when you use a filter. Without a filter, you don't really have much of a nitrogen cycle and even with filters, I don't really recommend using bacteria additives.

I hope your guy perks up soon. One thing you might try to entice him to eat is soak his pellets in garlic juice. Garlic is an appetite stimulator so hopefully it will make him hungry again.

[Behati]

He seems hungry, he always comes to me swimming up to the top as if to ask me to feed him but he's refusing food. He has perked up a lot since I took him out, I will try the garlic juice. They'll eat themselves to death, not starve themselves to death right?

[Behati]

The garlic laced pellets aren't working, he keeps going for the food (has an appetite) but he keeps spitting everything out.

[fishy friend2]

It might be because they are to big maybe you could crush the pellets up

[Behati]

I tried crushing the pellets, he learned to turn away from them. That little .. bastard I got him freeze-dried bloodworms (because I'm kind of scared of live/frozen worms), and he nom'd it like no tomorrow. I gave him a little extra because I'm sure he's starving himself thin.

Now can someone tell me if I can feed freeze-dried bloodworms to him consistently if he turns his nose from pellets?

[Sakura8]

I wouldn't recommend it. It has high protein but it may lack in vitamins that pellets will supply. If the size of the pellets is a problem, you could try these: New Life Spectrum Small Fish Formula .5mm Sinking Pellets. They're super, super tiny. Otherwise, if he consistently refuses pellets, I'm afraid your next best choice would be frozen bloodworms or frozen brine shrimp. :/ If you use tweezers to feed them, it's not *too* bad. You could try flakes but I generally don't recommend them just because they really cloud up the water and make a mess.

[Behati]

I can definitely do brine shrimp though I'm not sure if he'll agree to eat it yet. I can change the water every 2 days or so if needed or at any slight cloudyness, but I'm not sure if he'd eat that. I'm going to see if I can feed him a pellet tomorrow. I know he came home having trouble with pellets although he still ate them. He'd spit them out and try again usually successfully. It's just after putting in that medication he suddenly stopped trying.

[Sakura8]

It may have temporarily killed off his appetite or sense of smell. Sometimes medicine does that. Hopefully his appetite will come back. I know how frustrating it is to have a fish who won't eat (currently have one right now ). Good luck with him and keep us posted.