Axolotl has swollen side of cloaca.

[GoldenAxolotol]

I have a 3 year old male axolotl. He was eating fine and pooped but when I went to change the tank water I noticed this. I have him in the fridge bit not sure what it is. Constipation does not make sense since he ate and pooped right before I saw this, not sure if it's a prolapse or infection ? The other axolotl in the tank looks fi. Maybe it bit him??? Any ideas would be appreciated !

 

[wolfen]

because of the redness above the cloaca it does look like an infection which will require antibiotics and vet assistance, placing in 100% holtfreters may help slow down the spread and will reduce the swelling if caused by prolapse.