Betta fish with small white fuzz, otherwise acts healthy and normal

Question
I have a male betta fish that otherwise looks and acts perfectly healthy - but there are three spots of fuzz that I can't get rid of despite changing the filter, doing water changes, and dosing with meds. The fish really seems to be fine - eating and everything as usual. But I'm worried that this will slowly get worse and I'm not sure what to do.

First, here are details that will probably be important:

Housing
What size is your tank? - 5 gallons
What temperature is your tank? - 80 degrees
Does your tank have a filter? - Yes, Whisper
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? 1 dwarf frog, 1 pleco

Food
What type of food do you feed your betta fish? - Hikari Betta bio-gold, 4 pellets a day. Once in a while I mix it up and give him a few freeze dried bloodworms.


Maintenance
How often do you perform a water change? - about 20% every 3 weeks
What type of additives do you add to the water when you perform a water change? - the water conditioner drops

Water Parameters:
Have you tested your water? No

Symptoms and Treatment
How has your betta fish's appearance changed?

- It started as an almost imperceptible white fuzzy spot (bigger than salt grains, more like...the size of post earring) on the pectoral fins. It's almost impossible to see - you really have to be watching the fish in the right light. The spots haven't gotten bigger or smaller. It's been about two months and nothing has changed with the pectoral fins, but today I noticed fuzziness hanging off the very trailing end of the caudal fin. But that's it - the fins aren't ragged, the color and behavior of the fish is otherwise exactly the same. He eats, builds bubble nests, everything the same.

Have you started treating your fish? If so, how?

When I first noticed the fuzz, I went to a aquarium store (a proper hobbyist one, not a Petsmart). The owner recommended E.M. Erythromyycin. I follow the instructions exactly. Nothing changed.

I am now trying my first dose of API General Cure. But if this doesn't do anything, I don't know if I should do another round of the E.M. Erythromycin or try something else.

Does your fish have any history of being ill? No.
How old is your fish (approximately)? I have had the fish since December of this year.(about 8 months on top of whatever age the fish was at purchase)

I'd like to know:

1) Is my tank overstocked?
2) Should I try increasing the heat?
3) What should I do next if the General Cure doesn't do anything?
4) Could he have gotten something from the freeze dried worms? Should I avoid them?

I would greatly appreciate some insight. Thank you!

Answer
Hi Tara

Please see below for my recommendations

1) Is my tank overstocked? Yes, a 5 gallon is fine for one Betta but much too small for a Pleco. A Pleco needs to be in at least a 30 gallon

2) Should I try increasing the heat? No, 78 - 82 is fine for a Betta

3) What should I do next if the General Cure doesn't do anything? Do a 50% water change then try Pimafix and follow the directions carefully. After treating with Pimafix for 7 days, do another 25% water change.

4) Could he have gotten something from the freeze dried worms? Should I avoid them? No, if Bloodworms are just offered occasionally as a treat, they are fine and will not make your Betta sick. Avoid giving him pellets, give him Tetramin Tropical Flakes. The Tetramin will provide him a well balanced diet.

Finally, your Betta needs a 25% water change every week, not 20% every 3 weeks. This is especially true in a smaller tank. After the Pimafix treatment, start doing 25% water changes every week. Change the carbon in your filter once a month.

Hope this helps, good luck!

Richard