Scale Issues With Platy

[djv35]

I have a platy that's been dealing with some kind of scale issue below.

Right around the top of his head looks like a blood spot with raised scales. There's a pimple looking thing at the base of the dorsal fin. And then two dark spots on the tail fin. I've tried researching what this is but I've found it tough to get a definitive answer. 

The fish is otherwise healthy (eating normally, behaving normally, active). No other fish has this issue, all the others are perfectly healthy.

I'm struggling to figure out what this is and how to treat. Any help is greatly appreciated.

Water Parameters:

• pH: ~ 6.9 - 7.2
• Nitrates: ~ 40 ppm
• Hardness: Soft water
• Nitrite: 0 ppm
• Ammonia: Typically 0 ppm. There was a temporary rise to 0.25 ppm when I tried some new chemicals in an attempt to slightly lower the nitrates. That is when the spot next to the dorsal fin appeared (everything else was there prior when the ammonia was consistently at 0 ppm).
• KH/Buffer: Unknown
• Water Temperature: ~ 78-80 deg F 
• FWIW, tank is heavily planted.

 

Edited June 14, 2021 by djv35

[quikv6]

I can't speak to the issue itself, directly, but I would suggest a reasonable degree of salt (I'd say 1 TBSP per 3 gallons would be a good start) as a first step. Platys should appreciate the salt. If you have plants, it would be wise to treat the platy in a separate tank/tub.

Also, going off your parameters, two things stuck out a bit: Low GH and unknown KH.

-Platys, like most livebearers, seem to like harder water with more minerals. Consider a Wondershell or Seachem Equilibrium/Replenish as a means to raise GH.

-Unknown KH would worry me. I'd be worried the buffer (KH) would be low, leaving the tank susceptible to a PH swing/crash. See if you can get a test strip that shows KH. If it is indeed low, you can add crushed coral to the substrate or filter to bring it up. The PH would probably rise a few tenths as well, and I think your platys will appreciate that too. Overall, it would just add more stability to the parameters/environment.

 

[Colu]

 it could be livebearer disease bought on by you low GH and possible low kH i would raise your as hardness as @quikv6 suggest I would treat with 1 table spoon for 2 gallons of aquarium salt for now