Odd behavior in Mandarin salamander

One of my two mandarins has been acting strange since yesterday morning. Normally during the day both of them hang out together in one of the hiding spots in the cage and come out to say hello if someone goes over there. Yesterday morning when I got up for work the more social of the two was hanging out in the water end of the terrarium. I thought it a little strange but didn't think much of it since he (or she) does go for a swim now and then.

But, as of this morning he (or she) is still hanging out in the water. His cloaca is swollen and he has a lump on his left side just in front of the rear legs. The lump has been there since I got him a year ago and hasn't changed. The abdomen is not distended and newt is eating normally (I thought maybe he was just begging for food so I tried feeding). He's just as social as usual and CAN get out of the water. He just crawled out as I'm sitting here typing, but in a couple of minutes he's going to go right back in.

Why would a terrestrial newt hang out in the water? I'm pretty sure this is my male, although I could be mistaken since the two look so similar. But either way it doesn't appear that the newt is gravid. I'm worried about him. Any ideas?

Is it possible your newt is becoming aquatic?

Take a photo just in case

Yeah, I have no experience with tylotriton, but I thought that most all newts breed in water. Perhaps he's entering breeding season? The caresheet says to give them enough water to breed in but to still keep a large land area (Caudata Culture Species Entry - Tylototriton shanjing under the breeding section). So if this is the case and he is in the mood for breeding, then you probably don't need to worry about him being in the water.

After re-reading the care sheets and information pages I'm thinking he's displaying breeding behavior. I turned the air pump off in the water end of their terrarium and since then he's been spending more time out of the water. I have them in a 20 long and the last 6 inches of it is a four inch deep aquatic area. He does go for a swim once in a while but I've never seen him spend so much time in the water. He sitting on his rock half in the water, half out it right now. It amazes me how much more social he is than my other newt, she only comes when I open the terrarium to feed them. He comes out if I walk in the room.

The pictures, the first one is a picture of their setup. The second is of the newts themselves. The one coming out of the water is the one thats been behaving strangely the last few days.

It looks really good.