I need some help with two of my neon tetras. I've had 5 neon tetras for about 5 weeks now. They were from a smaller tank and I just moved them into my 29 gallon tank about a week and a half ago. They are the only fish in there as I had been cycling it for weeks prior. They had been treated prior with aquarium salt and general cure. Recently I noticed one of the smaller ones had a slightly pointed stomach. In the picture its colors look faded because it was taken a week ago. The tetra has since gotten its color back but still has a sightly pointed stomach. It's more noticeable after eating. It swims, eats, and does everything else normal. It shows no other signs of sickness or problems. I asked an employee at a local Petco but they just said it could be a tumor and didn't seem to know more than I did. I've only been lightly feeding them when they were being treated, so could it just be skinny?
The second picture is a different fish. This one looks like something is on its mouth. I can't tell if it's an injury or something else growing. It doesn't look that big. It is acting normal and looks fine otherwise though. Can anyone tell me if I'm overreacting or what I should do? My nitrates have been higher the last couple days but I think it's because I moved some things in my tank and I uncovered some root tabs so they leached into the water column. Nitrate levels were about 60-80ppm the day after. I've done a couple water changes to get them back down to a normal level. Other levels stayed fine though.
I'm newer to the hobby so I'm nervous about infecting all my fish or having to start my tank over. Could these be connected?
Any help is appreciated as I would like to add more fish eventually and want everyone healthy!!
Ph-7.6
Ammonia- 0
Nitrite-0