Endler has possible tumors, contagious?

[Swred5]

I have an endler who started changing colors,  2 orange spots on one side of his body. He is about 6 months old and 1st time I've kept them, so figured it was maturing. This began 3 weeks ago. Spots grew in diameter and I couldn't tell if they were swelling,  but husband didn't think they were. Now they have gotten bumpy and swollen. He has continued eating and swimming normally. I moved him to a tank by himself (planted with tons of snails & red cherry shrimp) as another endler was nipping at one of the spots. The spots do not look to be open sores. Anyone experience this before?  He just won't stay still for picks.

Nitrites- 10 Nitrates-0 Chlorine-0 Water tests Very Hard kh-40-60 ph-7.3 

Any help is appreciated! 

[FrozenFins]

could be a tumor, if so its not contaigous. All though treatment is really hard and the only known treatment is surgery.

[Colu]

You could try aquarium salt 1 table for two gallons 

[Swred5]

Getting a better look, it looks like wen on a goldfish.  Is that even possible? He still is swimming around, eating and pooping fine. I still fear everytime I go to turn on the light or feed the tank he will have passed. I appreciate everyone who has read and replied.

[Kirsten]

Poor baby. Seems like cancer / tumors are possible in fish. For the tumor on its gills, it could be a thyroid issue (wondering if that's connected to his developing male-spots as well). Perhaps a little table salt w/iodine instead of aquarium salt would help? https://www.petmd.com/fish/conditions/cancer/c_fi_Cancer_and_Tumors

ETA: in any case, even if he recovers, please be sure he doesn't breed.

Edited January 16, 2021 by Kirsten