What's Wrong With My Betta turning a blackish (blue?)

So I got Zenny, my 'dragonscale' betta (I don't think he's a dragonscale) from petco about two weeks ago. When I first got him he seemed like he was the healthiest one at the store and was all white with a blue sheen, but just within the last week or so he started turning a blackish (blue?) throughout his entire body, and the edges of his fins, too. I also noticed that he doesn't have any scales on his head. I have started doing the aquarium salt treatment as he does seem like he has some fin rot going on. He is in a 3 gallon tank with a heater, but no filter as I have him in an aquafarm which is suppose to be an aquaponic system that uses plants as the biological filter on top of the zymbac (nitrifying bacteria) I've added when I first got him. I've also added driftwood and catappa leaves to his tank to help soften the water and he has a cory as a tank mate(in a separate tank at the moment due to the aquarium salt treatment). I just want to make sure I am doing the right things and that he's just going through color changes and not any other illness cause I can't seem to find anything related to what's happening to him. I've attached some pictures for reference. Also, from what I've researched, he really doesn't seem like a dragonscale if anyone has a better idea of what he might be, please let me know as well thanks!

 

Bettas often change colour, I believe dragonscales are known for that. So nothing to worry about apart from fin rot.

Also 3 gallons is a bit too small for a betta or a Cory, upgrade the betta to a 5 and the Cory to a 20 with five of its own species (at least)

 

Oh wow, my betta looks quite similar! He has the same black stripes on his fins as well and they have always been there.

 

Salt won't treat fin rot. Fin rot is almost always caused by poor water quality, and since you said you don't have a filter, that's the problem. Do daily water changes and keep his water "clean" and the rin rot will clear up.

 

So I got Zenny, my 'dragonscale' betta (I don't think he's a dragonscale) from petco about two weeks ago. When I first got him he seemed like he was the healthiest one at the store and was all white with a blue sheen, but just within the last week or so he started turning a blackish (blue?) throughout his entire body, and the edges of his fins, too. I also noticed that he doesn't have any scales on his head. I have started doing the aquarium salt treatment as he does seem like he has some fin rot going on. He is in a 3 gallon tank with a heater, but no filter as I have him in an aquafarm which is suppose to be an aquaponic system that uses plants as the biological filter on top of the zymbac (nitrifying bacteria) I've added when I first got him. I've also added driftwood and catappa leaves to his tank to help soften the water and he has a cory as a tank mate(in a separate tank at the moment due to the aquarium salt treatment). I just want to make sure I am doing the right things and that he's just going through color changes and not any other illness cause I can't seem to find anything related to what's happening to him. I've attached some pictures for reference. Also, from what I've researched, he really doesn't seem like a dragonscale if anyone has a better idea of what he might be, please let me know as well thanks!View attachment 438413 View attachment 438414

It’s not bad for a Betta to change colors! Mine did within the first 2 days of having him. It means he has been well taken care of and is healthy. When I got him is was light blue and pink, after a could days he turned dark blue and red. Aside from possible fin rot, Zenny looks beautiful!

Also, I agree with the person who said you have the wrong size tank. Bettas should be in no less than a 5 gallon and Corys in no less than a 20 with at least 5 others. I made the mistake of only getting 2 Corys; I still have to get 4 more.

 

I am currently on day 2 of doing daily water changes with the aquarium salt to help him recover and just ordered a minI filter. How about his scaleless head though? Will they eventually grow back?

 

I am currently on day 2 of doing daily water changes with the aquarium salt to help him recover and just ordered a minI filter. How about his scaleless head though? Will they eventually grow back?

Their heads do not have visible scales unless they have diamond eye.

 

Got it thank you guys so much for the advices! One last question I have regarding aquarium salt is once I’m done treating him with it do I need to gradually lessen the amount of salt and eventually back to freshwater or can I just stop?

Oh wow, my betta looks quite similar! He has the same black stripes on his fins as well and they have always been there.

Your betta is beautiful! I hope Zenny grows to be just as gorgeous!