Two new problems have cropped up in my tank after a blissful period of everything going smoothly
I was wondering if anyone could shed some light on these symptoms and help me treat them if necessary 
Tank size: 207 liters
pH: 6,8
ammonia: 0ppm
nitrite: 0ppm
nitrate: <5.0ppm (Somewhat worried about that, that reading has never come up before
)
tank temp: 24-25C (Will be getting a new heater on Tuesday as it seems dodgy)
Fish Symptoms (include full description including lesion, color, location, fish behavior):
Problem NO.1, female betta: This is what is concerning me the most at the moment. It started off with a few of her scales looking like she'd had a knock and they were slightly loose. I had a closer look the other day to check on how she was and noticed that there are now small white things protruding from the areas where the scales were slightly raised. They're tiny and don't move as far as I can tell, but I was wondering if they could be some form of parasite? No other fish are showing the same symptoms.
Problem NO.2, male Laetacara Araguaiae: He has developed a pale grey "patch" on his flank towards his fin. It's not fluffy, nor raised or crusty. It almost looks like he's burnt himself, but I don't want to chance just leaving it in case it's something else. It hasn't spread, the area around it doesn't look inflamed or sore.
Volume and Frequency of water changes: Every week 30% and gravel vac.
Chemical Additives or Media in your tank: Water conditioner only.
Tank inhabitants: 9 female betta, 1 pearl gourami, 2 laetacara araguaiae and 7 Rasbora espei
Recent additions to your tank (living or decoration): 7 Rasbora espei on the 18th December. These are showing no symptoms at all.
Exposure to chemicals: None
Digital photo (include if possible):
Female betta (sorry the quality is awful, she's dark in colouration and wouldn't stay still)
Male laetacara:
Both are eating very well with the rest of the tank of a diet of flakes, various frozen worms, frozen peas and cucumber.
I'd be really grateful if anyone could give me some advice on either issue
Tank size: 207 liters
pH: 6,8
ammonia: 0ppm
nitrite: 0ppm
nitrate: <5.0ppm (Somewhat worried about that, that reading has never come up before

tank temp: 24-25C (Will be getting a new heater on Tuesday as it seems dodgy)
Fish Symptoms (include full description including lesion, color, location, fish behavior):
Problem NO.1, female betta: This is what is concerning me the most at the moment. It started off with a few of her scales looking like she'd had a knock and they were slightly loose. I had a closer look the other day to check on how she was and noticed that there are now small white things protruding from the areas where the scales were slightly raised. They're tiny and don't move as far as I can tell, but I was wondering if they could be some form of parasite? No other fish are showing the same symptoms.
Problem NO.2, male Laetacara Araguaiae: He has developed a pale grey "patch" on his flank towards his fin. It's not fluffy, nor raised or crusty. It almost looks like he's burnt himself, but I don't want to chance just leaving it in case it's something else. It hasn't spread, the area around it doesn't look inflamed or sore.
Volume and Frequency of water changes: Every week 30% and gravel vac.
Chemical Additives or Media in your tank: Water conditioner only.
Tank inhabitants: 9 female betta, 1 pearl gourami, 2 laetacara araguaiae and 7 Rasbora espei
Recent additions to your tank (living or decoration): 7 Rasbora espei on the 18th December. These are showing no symptoms at all.
Exposure to chemicals: None
Digital photo (include if possible):
Female betta (sorry the quality is awful, she's dark in colouration and wouldn't stay still)

Male laetacara:

Both are eating very well with the rest of the tank of a diet of flakes, various frozen worms, frozen peas and cucumber.
I'd be really grateful if anyone could give me some advice on either issue
