Help- Betta with one swollen eye, lump on tail

[divemaster24]

I’ve been out of town for five days (husband has been caring for animals) and returned this AM to find my betta sitting on the bottom with a lump/tumor on his side near his tail and one enlarged eye. He came up for food and is swimming around now. He has one mystery snail as a tank mate. Water parameters were fine (0 ammonia, 0 nitrites, 50 nitrates, temp 81, pH 7.4) but I did a 60% water change anyway. Please help!

[xXInkedPhoenixX]

Oh my @divemaster24 that looks awful- poor thing! It's really hard for me to say for sure but I think that's all an injury- maybe his tail or head got caught and in doing so injured the other. Usually with just one eye popped out it's injury not illness and the tail looks like ripped/injured scales. Test your water parameters ASAP make sure you have 0/0 ammonia and nitrite right away. Keep the water SUPER CLEAN- you can add aquarium salt to help with any potential bacteria infection and keep an eye on it for fungus as you may have to dose meds (so make sure now you have meds on hand for both bacterial and fungus infections if you don't have them go get them). @Colu might have other insights as to medicating or possible diagnosing. 

Fungal infections will look fuzzy around the area of injury. 

I'd also check the tank for areas he could have gotten injured. I see some jagged rock in your tank- make sure that's not too close to the tank walls, make sure he has clearance around and behind things. 

Edited May 30, 2022 by xXInkedPhoenixX

[Colu]

 bilateral Popeye is usually caused by an injury if it were unilateral Popeye I would suspect a bacterial infection I agree with @xXInkedPhoenixXI think that's an injury  I would recommend doing a course of kanaplex in food to help provent any secondary bacterial infection you could also add a small amount of aquarium salt 1 table spoon for 5 gallons that shouldn't harm your plants at that level will help provent any secondary fungal infections setting in on the wound